tag:blogger.com,1999:blog-63344469349223015362024-02-22T19:30:28.591+00:00Neutrino BlogSwimming in a sea of the shyest, strangest and smallest things in our Universe: Neutrinos.Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.comBlogger66125tag:blogger.com,1999:blog-6334446934922301536.post-21486430189399869382020-04-13T16:30:00.000+01:002020-04-13T16:30:45.974+01:00YouTube VideosI have been spending a lot of my time over the past few weeks locked down in my house because of COVID-19. So I thought I'd get some LEGO out and make some explainer videos to explain as much as I could about the standard model using these fantastic little bricks. Much of these videos are based upon ideas that first started here on this very blog before making it into my book Particle Physics Brick by Brick.<br />
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The first video embedded below is really there to justufy my use of my favourite toy! But I also hope it says something worthwhile about the use of analogy in science education.<br />
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The second video is a brief introduction to the field of particle physics and the standard model.<br />
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Please do give them a watch, like and leave nice comments if you feel it appropriate.<br />
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More videos to follow in two days...<br />
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Thanks!Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com3tag:blogger.com,1999:blog-6334446934922301536.post-62644077350720138652018-03-16T21:32:00.000+00:002018-03-16T21:32:28.069+00:00Particle Physics Brick by Brick<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGtthLRMct1xZ6qN-6u82Uw0gNP1AvGwlssuocwhksCD_BYVqhL0oK8xHII0aK8E5pgjr_zFuBa3KB42hY8XNkMFST2WnIql2fWjUW4Q_rn_KAslvxMHtFehPC_EW3S59oeqCpfoRJ2vk/s1600/Cover.jpeg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="650" data-original-width="525" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGtthLRMct1xZ6qN-6u82Uw0gNP1AvGwlssuocwhksCD_BYVqhL0oK8xHII0aK8E5pgjr_zFuBa3KB42hY8XNkMFST2WnIql2fWjUW4Q_rn_KAslvxMHtFehPC_EW3S59oeqCpfoRJ2vk/s320/Cover.jpeg" width="258" /></a></div>
It has been a very long time since I last posted and I apologise for that. I have been working the LEGO analogy, as described in the pentaquark series and elsewhere, into a book. The book is called Particle Physics Brick by Brick and the aim is to stretch the LEGO analogy to breaking point while covering as much of the standard model of particle physics as possible. I have had enormous fun writing it and I hope that you will enjoy it as much if you choose to buy it.<br />
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It has been available in the UK since September 2017 and you can buy it from <a href="http://foyles.co.uk/witem/science-mathematics/particle-physics-brick-by-brick,ben-still-9781844039340">Foyles</a> / <a href="https://www.waterstones.com/book/particle-physics-brick-by-brick/dr-ben-still/9781844039340"> Waterstones </a> / <a href="http://bookshop.blackwell.co.uk/bookshop/product/Particle-Physics-Brick-by-Brick-by-Dr-Ben-Still/9781844039340"> Blackwell's </a> / <a href="https://www.amazon.co.uk/Particle-Physics-Brick-Ben-Still/dp/184403934X/ref=sr_1_1"> AmazonUK</a> where it is receiving ★★★★★ reviews<br />
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It is released in the US this Wednesday 21st March 2018 and you can buy it from all good book stores and <a href="https://www.amazon.com/Particle-Physics-Brick-Subatomic-Explained/dp/0228100127">Amazon.com </a><br />
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I just wanted to share a few reviews of the book as well because it makes me happy!<br />
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<i>Spend a few hours perusing these pages and you'll be in a much better
frame of mind to understand your place in the cosmos... The
astronomically large objects of the universe are no easier to grasp than
the atomically small particles of matter. That's where Ben Still comes
in, carrying a box of Legos. A British physicist with a knack for
explaining abstract concepts... He starts by matching the weird
properties and interactions described by the Standard Model of particle
physics with the perfectly ordinary blocks of a collection of Legos.
Quarks and leptons, gluons and charms are assigned to various colors and
combinations of plastic bricks. Once you've got that system in mind,
hang on: Still races off to illustrate the Big Bang, the birth of stars,
electromagnetism and all matter of fantastical-sounding phenomenon,
like mesons and beta decay. "Given enough plastic bricks, the rules in
this book and enough time," Still concludes, "one might imagine that a
plastic Universe could be built by us, brick by brick." Remember that
the next time you accidentally step on one barefoot.</i>--<a href="https://www.washingtonpost.com/entertainment/books/everything-explained--in-photos-cartoons-and-legos/2017/12/27/a3da9846-e75e-11e7-a65d-1ac0fd7f097e_story.html">Ron Charles, The Washington Post</a><br />
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<a class="a-size-base a-link-normal review-title a-color-base a-text-bold" data-hook="review-title" href="https://www.amazon.co.uk/gp/customer-reviews/RZGVHB0HK2J1W/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=184403934X">Complex topics explained simply</a> <span class="a-size-base review-text" data-hook="review-body"><i>An
excellent book. I am Head of Physics at a school and have just ordered
60 copies of this for our L6th students for summer reading before
studying the topic on particle physics early next year. Highly
recommended.</i> - Ben </span><span class="a-size-base review-text" data-hook="review-body">★★★★★ <a href="https://www.amazon.co.uk/Particle-Physics-Brick-Ben-Still/dp/184403934X/ref=zg_bs_278422_7?_encoding=UTF8&psc=1&refRID=P4GNSSS78PQCY9XJF6BX">AmazonUK</a></span><br />
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<a class="a-size-base a-link-normal review-title a-color-base a-text-bold" data-hook="review-title" href="https://www.amazon.co.uk/gp/customer-reviews/RLIAJQCGL7PST/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=184403934X">It's beautifully illustrated and very eloquently explains the fundamentals of particle ...</a><br />
<span class="a-size-base review-text" data-hook="review-body">This is a
gem of a pop science book. It's beautifully illustrated and very
eloquently explains the fundamentals of particle physics without hitting
you over the head with quantum field theory and Lagrangian dynamics.
The author has done an exceptional job. This is a must have for all
students and academics of both physics and applied maths! - Jamie </span><span class="a-size-base review-text" data-hook="review-body">★★★★★ <a href="https://www.amazon.co.uk/Particle-Physics-Brick-Ben-Still/dp/184403934X/ref=zg_bs_278422_7?_encoding=UTF8&psc=1&refRID=P4GNSSS78PQCY9XJF6BX">AmazonUK</a></span> <br />
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Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-59360346856262407972015-07-31T15:10:00.000+01:002015-07-31T15:16:12.185+01:00Pentaquark Series 5: Now You See Me, Now You Don't<i style="text-align: justify;"><span style="-webkit-text-stroke-width: initial; color: #333333; font-family: 'Helvetica Neue Light', HelveticaNeue-Light, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-weight: normal; line-height: 19px;">This is the fifth in a series of posts I am releasing over the next two weeks, aimed at covering the physics behind Pentaquarks, the history of "discovery", and the implications of the latest results from LHCb. </span><a href="http://This is the fourth in a series of posts I am releasing over the next two weeks, aimed at covering the physics behind Pentaquarks, the history of "discovery", and the implications of the latest results from LHCb. Post 3 here. Today we discuss the prediction of pentaquarks and first tentative sightings." style="color: #333333; font-family: 'Helvetica Neue Light', HelveticaNeue-Light, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-weight: normal; line-height: 19px;">Post 4 here</a><span style="color: #333333; font-family: Helvetica Neue Light, HelveticaNeue-Light, Helvetica Neue, Helvetica, Arial, sans-serif;"><span style="font-weight: normal; line-height: 19px;">.</span><span style="-webkit-text-stroke-width: initial; font-weight: normal; line-height: 19px;"> Today we discuss the discovery and subsequent </span><span style="font-weight: normal; line-height: 19px;">undiscovery</span><span style="-webkit-text-stroke-width: initial; font-weight: normal; line-height: 19px;"> of the </span><span style="font-weight: normal; line-height: 19px;">theta-plus</span><span style="-webkit-text-stroke-width: initial; font-weight: normal; line-height: 19px;"> exotic baryon and evidence for the P</span><span style="-webkit-text-stroke-width: initial; font-weight: normal; line-height: 19px;"><span style="font-size: xx-small;">c</span> particle seen by LHCb in 2015.</span></span></i><br />
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Now You See Me, Now You Don’t</span></h2>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6WxF3Do_O4IBEEiTAvaJ6Ils1G5JG1wkECDZuvgAXFX74fszIr80BSVpLJ9tgrk1gUxT42hIfggZMFnLdRvW6fcMToBzqzxUTRFRsiNse00k3bz8o5JXD-g37bI8vFhKjJM2CYb8rNK0/s1600/Theta_plus.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="315" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6WxF3Do_O4IBEEiTAvaJ6Ils1G5JG1wkECDZuvgAXFX74fszIr80BSVpLJ9tgrk1gUxT42hIfggZMFnLdRvW6fcMToBzqzxUTRFRsiNse00k3bz8o5JXD-g37bI8vFhKjJM2CYb8rNK0/s400/Theta_plus.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The possible configurations of the theta-plus either a pentaquark <br />particle where all quarks are bound together (left) or as a <br />molecule made from a bound Baryon and Meson (right).</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">With evidence of an excess in data being presented by 10 different experiments the existence of the Θ<sup>+ </sup>pentaquark (or Baryon-Meson molecule) was looking ever more like a discovery. Further still, some small statistics evidence was also mounting for two other pentaquark states. Many other experiments joined the search but most were coming up empty handed. One explanation for this is that they could have been using different experimental methods? Using different energies of particle maybe? It is a difficult task to disentangle all of the differences between experiments, but it is an essential one. Experimental data is always compared to theory, or theory to experiment, so that the behaviour of nature may be written into mathematical language. To interpret experimental results one must understand every aspect of the machinery of an experiment as well as any known physics which may contributes in some way to a measurement being made. </span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Many of the experiments claiming to have evidence of the Θ<sup>+ </sup>particle were different in a number of ways to the other experiments who were claiming to see no evidence for its existence. There were two pairs of experiments, however, which had minimal difference between them and proved to be the most compelling cases for comparing results. The DIANA [1] experiment claimed to have seen a particle fitting the description of the Θ<sup>+ </sup>created via a interaction known as charge exchange. At the same energies and via the same interaction channel </span><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">(type)</span><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"> the Belle experiment sat looking at many more interactions than DIANA. With a much larger data set, containing a great deal more charge exchange interactions, the Belle could see no evidence [2] of the Θ</span><sup style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">+ </sup><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">candidate particle seen by DIANA. </span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The other pair of experiments, also at odds with one another, were SAPHIR and CLAS. The SAPHIR experiment used a type of particle interaction known as photo-production; photons of light are collided with other particles to instigate an interaction, in this case producing two pairs of quark and antiquark. SAPHIR produced one of the most, statistically speaking, convincing evidence of all the ten experiments claiming to have seen a particle looking like Θ<sup>+</sup>[3]. With this in mind the CLAS experiment repeated the conditions used by SAPHIR and took a great deal more data. If the Θ<sup>+ </sup>particle was indeed there then CLAS would have enough data to prove its existence beyond reasonable doubt. CLAS saw no evidence at all for a Θ<sup>+</sup>-like particle [4]. The benchmark used to compare the experiments was the comparison between the number of possible Θ<sup>+ </sup>produces and the number of Lambda baryons made. When the number of possible </span><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Θ</span><sup style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">+ </sup><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">particles</span><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"> was divided by the number of Lambda baryons it was over 50 times lower in the CLAS result than that reported by SAPHIR. One of the most convincing pieces of evidence for the existence of the Θ</span><sup style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">+</sup><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"> particle was now seen to have been entirely refuted; by an almost identical experimental method with a lot more data backing it up. In the 2006 Particle Data Group review of the status of the Θ</span><sup style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">+ </sup><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">particle it was remarked of these results that </span><i style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">“Combined with the other negative reports, it leaves the reality of the Θ+ in great doubt.”</i></div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfu0g_FxMhIz_oMMsNabfEzedCOT3_bkD-j4dbAgqYRzJu55LG1JpMw5Nf3rm3BM3EvJI104oeer7VEVeY-Z64pPUNz5XDMzqPK5_GzsJPVjUevHzu1VZCrg0omzPeFCFtKa_Ga_fdZhU/s1600/Decay_Lambda_b0_pentaquark.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfu0g_FxMhIz_oMMsNabfEzedCOT3_bkD-j4dbAgqYRzJu55LG1JpMw5Nf3rm3BM3EvJI104oeer7VEVeY-Z64pPUNz5XDMzqPK5_GzsJPVjUevHzu1VZCrg0omzPeFCFtKa_Ga_fdZhU/s1600/Decay_Lambda_b0_pentaquark.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">A LEGO diagram showing the creation of a P<span style="font-size: xx-small;">c</span> pentaquark in the decay of a Lambda baryon.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Now, in 2015, the LHCb experiment has claimed very, statistically, convincing evidence of another particle [5]. This is an exotic (not your usual) baryon which seems to decay into a (not exotic at all) Baryon and a Meson. The results can be once again best understood as the decay of some particle containing four quarks and one antiquark. The quark content of this new particle cannot be the same as the Θ<sup>+ </sup>particle claimed by previous experiments; it is has a much greater mass and produces different particles when it decays. The baryon seen in the decay is a proton, made from two up quarks and a single down; the meson a J/</span><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: 'Lucida Grande';">Ψ,</span><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"> which is made from a charm quark and charm antiquark. The quark content of this particle is therefore: 2x up quarks, 1x down quark, 1x charm quark, and 1x charm antiquark. The pentaquark was seen to be an intermediate state in the decay of a L</span><sup style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">0</sup><sub style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">b</sub><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"> baryon see the LEGO diagram above.</span></div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLLC4Ig7SftF0OAYI8NglLap3HSu8gkhXzd_aJf86dFWSdTLca_jA2zYLEcFbMv2fB2y_inD0SjREHMcmA8CPN0y9FJyo2HQ_Q6S94NuDLKAVh1GoKwdXC9r7qJh3apFIMJiLby7UBIjY/s1600/Pc_LHCb.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLLC4Ig7SftF0OAYI8NglLap3HSu8gkhXzd_aJf86dFWSdTLca_jA2zYLEcFbMv2fB2y_inD0SjREHMcmA8CPN0y9FJyo2HQ_Q6S94NuDLKAVh1GoKwdXC9r7qJh3apFIMJiLby7UBIjY/s1600/Pc_LHCb.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The P<span style="font-size: xx-small;">c</span> state measured by LHCb could be a pentaquark (left) <br />or a Baryon-Meson molecule (right).</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The pentaquark was seen to exist in two forms, each just with slightly different masses - something not uncommon for particles made of quarks (explained in a future post). The majority of the mass of baryons, Mesons, and exotic quark particles comes not from the quarks themselves but instead from the strong force binding them together. A slight difference in configuration means a difference in energy and therefore mass os a particle. This will be the topic of the next blog post. The individual evidence for each pentaquark state combined to make an ever more convincing body of evidence that the particle, Pc, exists. </span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">[1] </span><a href="http://arxiv.org/abs/hep-ex/0304040"><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Observation of a baryon resonance with positive strangeness in K+ collisions with Xe nuclei, </span><span style="-webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">DIANA Collaboration, </span><span style="-webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">http://arxiv.org/abs/hep-ex/0304040</span></a></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">[2] <a href="http://arxiv.org/abs/hep-ex/0411005">Search for pentaquarks at BELLE, BELLE Collaboration, http://arxiv.org/abs/hep-ex/0411005</a></span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">[3] </span><a href="http://arxiv.org/abs/hep-ph/0310019"><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Exotic Theta^+ baryon production induced by a photon and a pion, SAPHIR Collaboration, </span><span style="-webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">http://arxiv.org/abs/hep-ph/0310019</span></a></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">[4] <a href="http://arxiv.org/abs/hep-ex/0510061"><span style="line-height: 28.799999237060547px;">Search for </span><span style="white-space: nowrap; word-spacing: normal;">Θ</span><span style="white-space: nowrap; word-spacing: normal;">+</span><span class="mo" id="MathJax-Span-8" style="border: 0px; display: inline; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap; word-spacing: normal;">(</span><span class="mn" id="MathJax-Span-9" style="border: 0px; display: inline; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap; word-spacing: normal;">1540</span><span class="mo" id="MathJax-Span-10" style="border: 0px; display: inline; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap; word-spacing: normal;">) </span><span style="line-height: 28.799999237060547px;">pentaquark in high statistics measurement </span><span style="line-height: 28.799999237060547px;">at CLAS, CLAS Collaboration, http://arxiv.org/abs/hep-ex/0510061</span></a></span><br />
<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">[5] <a href="http://arxiv.org/abs/1507.03414">Observation of resonances consistent with pentaquark, LHCb Collaboration, http://arxiv.org/abs/1507.03414</a></span><br />
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<i style="color: #333333; font-family: 'Helvetica Neue Light', HelveticaNeue-Light, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; line-height: 19px; text-align: justify;">Next time: The strong force and gluons.</i><br />
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Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com7tag:blogger.com,1999:blog-6334446934922301536.post-79027829810353775712015-07-22T13:53:00.000+01:002015-07-31T15:14:24.294+01:00Pentaquark Series 4: Pentaquark Prediction and Search<i style="text-align: justify;"><span style="color: #333333; font-family: Helvetica Neue Light, HelveticaNeue-Light, Helvetica Neue, Helvetica, Arial, sans-serif;"><span style="-webkit-text-stroke-width: initial; font-size: 14px; line-height: 19px;">This is the fourth in a series of posts I am releasing over the next two weeks, aimed at covering the physics behind Pentaquarks, the history of "discovery", and the implications of the latest results from LHCb. </span></span><a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-3-antiquarks-and-anti.html" style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; color: #333333; font-family: 'Helvetica Neue Light', HelveticaNeue-Light, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; line-height: 19px;">Post 3 here.</a><span style="color: #333333; font-family: Helvetica Neue Light, HelveticaNeue-Light, Helvetica Neue, Helvetica, Arial, sans-serif;"><span style="-webkit-text-stroke-width: initial; font-size: 14px; line-height: 19px;"> Today we discuss the prediction of pentaquarks and first </span><span style="font-size: 14px; line-height: 19px;">tentative sightings</span><span style="-webkit-text-stroke-width: initial; font-size: 14px; line-height: 19px;">.</span></span></i><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6sZR9b7sy2VgOduHeS_n3yky5o0gX7d0w1CDYZW1OhEC2N4AVuFInkNtbjC6LAqttiLV74mu757iQw1ygLTpMBQarouZD-pVgIa9nZ1Yo288yZ2nXndSVPMCOkUIkMzq9nKsNr17o5aQ/s1600/screen_shot_2015-07-14_at_08.13.25.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6sZR9b7sy2VgOduHeS_n3yky5o0gX7d0w1CDYZW1OhEC2N4AVuFInkNtbjC6LAqttiLV74mu757iQw1ygLTpMBQarouZD-pVgIa9nZ1Yo288yZ2nXndSVPMCOkUIkMzq9nKsNr17o5aQ/s320/screen_shot_2015-07-14_at_08.13.25.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The pentaquark might be a whole new type of particle <br />containing 4 quarks and 1 antiquark within itself.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Particle as announced by LHCb last week would have to be comprised of four quarks and one antiquark in some, currently, unknown arrangement. All quarks could be contained within some single particle; this is a pentaquark, or they could be a bound pair of one Baryon and one Meson - a Baryon-Meson molecule. From what we have discussed so far about the strong force there should be nothing stopping us from creating pentaquarks or Baryon-Meson molecules. A white strong charge Baryon plus a white strong charge Meson would simply result in a white strong charge bound molecule. Also if we have 4 quarks and 1 antiquark we can also create a white charge pentaquark in a number of different ways:</span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><span style="color: red;">red</span> + <span style="color: lime;">green</span> + <span style="color: blue;">blue</span> + <span style="color: red;">red</span> + <span style="color: cyan;">anti-red</span> = <span style="background-color: black;"><span style="color: white;">white</span></span></span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><span style="color: red;">red</span> + <span style="color: lime;">green</span> + <span style="color: blue;">blue</span> + <span style="color: lime;">green</span> + <span style="color: magenta;">anti-green</span> = <span style="background-color: black; color: white;">white</span></span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><span style="color: red;">red</span> + <span style="color: lime;">green</span> + <span style="color: blue;">blue</span> + <span style="color: blue;">blue</span> + <span style="color: yellow;">anti-blue</span> = <span style="background-color: black;"><span style="color: white;">white</span></span></span></div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_oaT9ZBBlT7do7ReWL9KlmY5X6tR9rOAg0UT7P8THf0XKXdT4LKa6MkwyI_-Ieam1G7DFzbWKqb1yOraqntAy3FChzNVKbXpe1z8ePDKDt7zDAXLeXGQCpiaypUHWG8_80kgjWiBmwX8/s1600/screen_shot_2015-07-14_at_08.13.14-2.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_oaT9ZBBlT7do7ReWL9KlmY5X6tR9rOAg0UT7P8THf0XKXdT4LKa6MkwyI_-Ieam1G7DFzbWKqb1yOraqntAy3FChzNVKbXpe1z8ePDKDt7zDAXLeXGQCpiaypUHWG8_80kgjWiBmwX8/s320/screen_shot_2015-07-14_at_08.13.14-2.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Or the pentaquark might be a bound <br />state of a Baryon and Meson.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">In <a href="http://arxiv.org/abs/hep-ph/9703373">1997 Dmitri Diakonov, Victor Petrov, and Maxim Polyakov [1]</a> employed similar methods to Gell-Mann in his Eightfold way, using the symmetries of the quarks to predict not only the existence but also the expected mass of pentaquark particles. Again like Gell-Mann they predicted a pattern in these symmetries called an Exotic Baryon anti-decuplet; exotic because these particles (or combinations thereof) are not constructed in the same way as other Baryons; baryon because they have some properties common with Baryons (there is at least one baryon’s worth of quarks making up these particles); anti-decuplet because there were 10 particles, as in Gell-Mann’s decuplet, but pointing in the opposite direction. I have drawn one representation of this anti-decuplet below using my LEGO analogy*. This is just one of a number of patterns that can be, and have been, drawn from quark symmetries.</span></div>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The Exotic Baryon Anti-decuplet: an extension of quark symmetries showing the lightest possible pentaquark states. Here I show the states as Baryon-Meson molecules.</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijMAONGEyX2ycddb9NxHsObuAddnkj1hXETF_jddOVJOmSNHCFLjVUcl_s7sPwJuniZNL4m1bTP_zvXdEteKQT02-oIIvcHPZIUd56DvgxEn3bSMTDpyzirkt1V6UYib1a9ZMCntxXg_I/s1600/Pentaquark_Baryon_antidecuplet.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="514" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijMAONGEyX2ycddb9NxHsObuAddnkj1hXETF_jddOVJOmSNHCFLjVUcl_s7sPwJuniZNL4m1bTP_zvXdEteKQT02-oIIvcHPZIUd56DvgxEn3bSMTDpyzirkt1V6UYib1a9ZMCntxXg_I/s640/Pentaquark_Baryon_antidecuplet.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The Exotic Baryon Anti-decuplet: an extension of quark symmetries showing the lightest possible pentaquark states. Here I show the pentaquark states as 4 quark, 1 antiquark bound states.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">With the prediction out there it is was now the job of the experimentalists to smash particles into one another and sift through the debris to see if any of these particles existed. They chose to focus their searches upon those particles at the extreme points of the anti-decuplet triangle. The lighter particles produced when these pentaquarks decay can only be explained by these exotic states. Let us take the Θ<sup>+</sup> as an example.</span></div>
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<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; font-size: x-small;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Detection of particles used to reconstruct the <br />pentaquark state. Borrowed from <a href="http://dnp-old.nscl.msu.edu/current/pentaquark.html">here.</a></span></span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The Θ<sup>+</sup> can be identified experimentally by the fact it is uniquely strange. The Θ<sup>+</sup> contains an anti-strange quark while all three quark baryons can only contain a strange quark, because no baryon contains an antiquark. We can say that the Θ<sup>+ </sup>has an opposite strangeness to all traditional Baryons; this is something that can be identified in particle detectors. The Θ<sup>+</sup> is similar to Baryons as it has the same quality known as baryon number; related to the colour charge of the quarks and antiquarks. Both pentaquarks and three quark Baryons have a baryon number of 1; each quark has baryon number +1/3 and the antiquark has baryon number -1/3. Experiments have shown that the strangeness and baryon number must be conserved when a particle decays to other lighter particles. By tracking strangeness and baryon number, experiments are able to pick out groups of particles which could only have come from the decay of a pentaquark. As we will discuss in future posts, this shows up in experimental data as a large amount of extra data around a single particle mass which sits on top of a broad number of other possible background data.</span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><span style="-webkit-text-stroke-width: initial;">In </span><a href="http://arxiv.org/abs/hep-ex/0301020" style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial;">2003 the LEPS experiment in Japan published a paper [2]</a><span style="-webkit-text-stroke-width: initial;"> which suggested evidence that a particle with a mass the same as the Θ</span><sup style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial;">+ </sup><span style="-webkit-text-stroke-width: initial;">(within errors) had been seen within its detectors. Over the next year this claim was followed by some nine other experiments all saying that they too had seen an excess in their data around the predicted Θ</span><sup style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial;">+ </sup><span style="-webkit-text-stroke-width: initial;">mass. The evidence for this pentaquark seemed compelling, but there were some problems and questions surrounding the data. In some cases the number of background events were underestimated, which </span>exaggerated and excesses there might have been.<span style="-webkit-text-stroke-width: initial;"> Some experiments chose specific techniques to enhance data around the predicted mass of the </span></span><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Θ</span><sup style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">+</sup><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">. <span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">When considering the results of all ten experiments the range of masses determined by each, although similar, varied far more than one would expect from the given theory. It was obvious that further experiments were needed, with much more data, if the existence of the Θ</span></span><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><sup style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">+ </sup><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">were to be confirmed or refuted.</span></span><br />
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<span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><i><span style="font-size: x-small;">*Notice I have not combined the quarks into a pentaquark particle but instead leave them next to one another as Baryon-Meson molecule..</span></i></span></div>
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<a href="http://arxiv.org/abs/hep-ph/9703373"><i><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">[1] </span></i><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><span style="font-style: italic; line-height: 24px;">D. Diakonov</span><span style="background-color: white; font-style: italic; line-height: 24px;">, </span><span style="font-style: italic; line-height: 24px;">V. Petrov</span><span style="background-color: white; font-style: italic; line-height: 24px;">, </span><span style="line-height: 24px;"><i>M. Polyakov, </i></span></span><span style="background-color: white;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><i>Z.Phys. A359 (1997) 305-314</i></span></span></a></div>
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<a href="http://arxiv.org/abs/hep-ex/0301020"><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><i>[2] </i></span><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><i><span style="line-height: 24px;">LEPS Collaboration</span><span style="background-color: white; line-height: 24px;">: </span><span style="line-height: 24px;">T. Nakano</span><span style="background-color: white; line-height: 24px;">, et al, </span></i></span><span style="background-color: white;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><i>Phys.Rev.Lett.91:012002,2003</i></span></span></a></div>
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<i style="color: #333333; font-family: 'Helvetica Neue Light', HelveticaNeue-Light, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; line-height: 19px; text-align: justify;"><a href="http://neutrinoscience.blogspot.co.uk/2015/07/this-is-fifth-in-series-of-posts-i-am.html">Next post: The search continues - the rollercoaster years leading up to the 2015 LHCb discovery.</a></i></div>
Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com3tag:blogger.com,1999:blog-6334446934922301536.post-32910035733316359322015-07-20T08:30:00.000+01:002015-07-23T18:03:56.833+01:00Pentaquark Series 3: Antiquarks and Anti-colour<div style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial;">
<i>This is the third in a series of posts I am releasing over the next two weeks, aimed at covering the physics behind Pentaquarks, the history of "discovery", and the implications of the latest results from LHCb. <a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-rule-of-three.html">Post 2 here.</a> Today we discuss particles that can be made from less than three quarks.</i></div>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Antiparticles have opposite properties like <br />electric charge.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Antiquarks and Anti-colour</span></h2>
<span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">In the <a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-rule-of-three.html">last post</a> I mentioned that particles made from quarks must be strong charge neutral, this can be achieved if each quark is colour charged with a primary colour of light (red, green, and blue) so that the overall colour charge of the particle is white. There is another way to build particles with a neutral, white colour, overall strong charge but for this we must talk about antiparticles. The three generations of fundamental particle also have mirror versions of themselves; the antiparticles. When you look into a mirror left becomes right but you still look the same size. A similar thing is true in the particle world - mirror antiparticle versions of particles have the same mass but they see the world in opposite ways. They see the world differently in the way they feel and interact through the forces of nature. We say an electron particle has a negative electric charge, then its antimatter version, the positron, will have a positive electric charge. The </span><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">anti-electron (positron) was first seen in experiment in 1932 (the same year the neutron was discovered), and since then it has been confirmed that antiparticles do indeed exist for all of the three generations of particle.</span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Antiquarks, the antimatter versions of the quark, also have their electric charges mirrored from positive to negative. As Antiquarks also feel the strong force they must also have their strong colour charges mirrored too - but what is an anti-colour? Let us think about the colours produced when mixing the primary colours of light. If we shine white light through a prism refraction splits it into a rainbow. Looking at the rainbow spectrum (diagram below) we see that directly in between the primary colours blue and green there is the colour cyan. It turns out that if we mix pure blue and pure green light we would see cyan as a result. As it is made up from two primary colours (green and blue) cyan is said to be a secondary colour. In-between green and red in the rainbow is another secondary colour; yellow. We would perceive the colour yellow from a mixture green and red light. What about a third secondary colour?</span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Rainbow spectrum of white light.</span></td></tr>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Mixing the three primary colours of light<br />to make the secondary colours and white.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The only mixture of primary colours not yet mentioned is red and blue; but wait - the colour in the middle of blue (at one end of the spectrum) and red (at the other end) is green. As I have already mentioned, green is a primary colour so it can’t be a secondary as well. The third and final secondary colour is not in fact a true rainbow colour at all, but one constructed by our mind. If we see blue and red light mixed we do not end up at green but instead we perceive the colour magenta. If you were to shine magenta light through a prism to split it into its component rainbow colours you would see the blue and red parts of the rainbow only. In this magenta 'rainbow' the middle green part would be entirely missing (see the spectra at the bottom). In this sense magenta is the anti-green - everything that green is not. To demonstrate this look at the optical illusion below (gif "borrowed" from <a href="http://blog.stevemould.com/the-curious-case-of-magenta/" style="font-size: 13px; text-align: center;">Steve Mould</a>)</span><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"> - stare at the centre cross. Do you see a green circle appearing? Now look away from the cross: a green circle is not present at all, what is in fact happening is that there is a lack of a magenta circle in the pattern not that a green one is appearing. Your mind is putting green where there is a lack of magenta!</span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Magenta: the anti-green. Image "borrowed" from <a href="http://blog.stevemould.com/the-curious-case-of-magenta/">Steve Mould</a></span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">So magenta is anti-green. It turns out that all three secondary colours are in fact the anti colours we are looking for to be the strong charges of our antiquarks. Cyan has no red if split by a prism, only green and blue, so is therefore anti-red. Yellow would not contain blue in its spectrum, just red and green, so is therefore anti-blue. We could then say that the opposite, antiparticle versions, of the red, green, and blue strong charges of quarks would be either cyan, magenta, or yellow.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT2qlZzIcav_28-U5fA5SpoXlVIBJSA_WXYtPXoe-IN0UMw-u34sTEyTtT0K9Pk2LchkGw50jdUGqG0IdP8TQNpck2c_LzfxQSfFcwY-CHs_2I7pEhwJjyfELlAwJNK9AGNE0F6Ok7CZU/s1600/QuarksAntiquarks.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="274" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT2qlZzIcav_28-U5fA5SpoXlVIBJSA_WXYtPXoe-IN0UMw-u34sTEyTtT0K9Pk2LchkGw50jdUGqG0IdP8TQNpck2c_LzfxQSfFcwY-CHs_2I7pEhwJjyfELlAwJNK9AGNE0F6Ok7CZU/s640/QuarksAntiquarks.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The whole set of Quarks and Antiquarks that are know to exist; they are one half of the building blocks <br />that make up all particles in our visible Universe.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Now what happens if we combine a quark with an anti quark? Magenta is made from red and blue, add green to it and you would have white light; yellow made from red and green, add blue and you get white light; cyan is made from blue and green, add red to it and you would get white light. So to create white, strong charge neutral, particles with quarks and antiquarks you would only need to have one quark and one antiquark. A green quark and a magenta antiquark; a red quark and a cyan antiquark; a blue quark and a yellow antiquark would all make particles. These quark-antiquark combinations are a group of particles called Mesons.</span><br />
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Just like the Baryons there is a pattern that Gell-Mann theorised in his Eightfold Way for the possible Meson particles that can be made from up, down and strange quarks; the Meson Octet (below). Mesons do not survive very long because particles and antiparticles are not very stable around one another. Generally when a particle meets its own antiparticle they annihilate one another to produce pure energy. Mesons, as they are constructed by quark and antiquark, use the first opportunity available to either form pure energy or a number of lighter particles. The middle row of the Meson Octet are particles called pions (π) which play a role in keeping protons and neutrons together in the nucleus but also in the production of <a href="http://neutrinoscience.blogspot.co.uk/2011/01/birth-death-and-neutrino-beams.html">neutrino particle beams</a>.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlrpQ9ZvrlwmXJE5w807ywJ6whKyEHb9_OYHAqHBMqZTJNyFnwiMo3wK12m6DswLO6cAS7r9KRA-FNBuF_ZwLFKTiEJai77YlW77BcDn767FmxFkPV_9xhN2E5x-YudaBS8eSgeV8SU3Y/s1600/MesonOctet.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="390" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlrpQ9ZvrlwmXJE5w807ywJ6whKyEHb9_OYHAqHBMqZTJNyFnwiMo3wK12m6DswLO6cAS7r9KRA-FNBuF_ZwLFKTiEJai77YlW77BcDn767FmxFkPV_9xhN2E5x-YudaBS8eSgeV8SU3Y/s400/MesonOctet.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The Meson Octet shows all possible Mesons that can be constructed <br />with up, down, strange, anti-down, anti-up, and anti-strange quark.</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiii_1UNtgul_oeIlc76hUYsxTqwqQpX4bNc2hNYENmQV-quvkUw2EAVFjnXSY3oknFH8ra3rm8Y9YqN4CdNl8f0EsZCqCI5wpauuJKXSMGOpGzUAdSeQUNCM41NYuOW2HhgKDXZBr3jK8/s1600/CYM_spectrum.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiii_1UNtgul_oeIlc76hUYsxTqwqQpX4bNc2hNYENmQV-quvkUw2EAVFjnXSY3oknFH8ra3rm8Y9YqN4CdNl8f0EsZCqCI5wpauuJKXSMGOpGzUAdSeQUNCM41NYuOW2HhgKDXZBr3jK8/s320/CYM_spectrum.png" width="260" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The refracted spectrum, or 'rainbow',<br /> of the secondary colours of light.</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCh_Bz3qKADYDD2RMIiFIlOJkdLz0QBjO-VysmuNBqoP8L5JDXMln4c-osCNfgVHo5RIMA4qfydRdeAsJtugqwIxAJyBoI6GdzFQr6ZIMWMxrJC9Wqium8P3wLac7-l9XjdGdQ_8pI7AA/s1600/RGB_spectrum.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCh_Bz3qKADYDD2RMIiFIlOJkdLz0QBjO-VysmuNBqoP8L5JDXMln4c-osCNfgVHo5RIMA4qfydRdeAsJtugqwIxAJyBoI6GdzFQr6ZIMWMxrJC9Wqium8P3wLac7-l9XjdGdQ_8pI7AA/s320/RGB_spectrum.png" width="260" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The refracted spectrum, or 'rainbow',</span><br />
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<i style="text-align: justify;"><span style="color: #333333; font-family: Helvetica Neue Light, HelveticaNeue-Light, Helvetica Neue, Helvetica, Arial, sans-serif;"><span style="font-size: 14px; line-height: 19px;"><a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-4-pentaquark.html">Next post: Pentaquark Prediction and Search - the prediction of the lightest pentaquark and first evidence they might exist.</a></span></span></i></div>
Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com2tag:blogger.com,1999:blog-6334446934922301536.post-8629399257948870052015-07-17T08:30:00.000+01:002015-07-23T18:03:14.267+01:00Pentaquark Series 2: Rule of Three...<i>This is the second in a series of posts I am releasing over the next two weeks, aimed at covering the physics behind Pentaquarks, the history of "discovery", and the implications of the latest results from LHCb <a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-what-are-quarks.html">(previous post here)</a>. Today we discuss why quarks like to come in threes.</i><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The two charges of the electromagnetic force and the <br />three charges of the strong force.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Rule of three …</span></h2>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Protons, neutrons, and other particles that are made up from 3 quarks are called Baryons. </span><span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">But why do they all have 3 quarks? Why not 4 or 6 or 10? It is all down to the way the strong force, responsible for binding the quarks together, works. The electromagnetic force has a possible two charges; which we label positive electric charge (like protons) and negative electric charge (like electrons). These different charges attract, which is the reason electrons remain orbiting the proton rich nucleus of an atom. The strong force it seems has not two but three possible charges! As there is no clear way to describe this in terms of whole numbers like positive and negative another analogy had to be found. The best way to think of strong charge is as colours of light. </span></div>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Overlapping light</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><i>**Disclaimer** Before I start talking of colours of light I want to clarify that I am not talking of colours and mixing that you may have come across when using paints or other pigments in art. Colours of light add to each other when mixed to create new colours. Colours of paint and and other pigments change because they subtract by absorbing different colours of light that is reflected from them.</i></span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The three primary colours of light we see are red, green, and blue. The reason we have decided upon these colours is a selfish biological one; our eyes have evolved to be sensitive in particular to these three colours individually. When these three colours are combined, added together, they form what we perceive as white light. If we assigned the three primary colours of light to the three possible strong charges we could say that a quark can have a strong charge of red, green, or blue. </span></div>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">It doesn't matter which of the quarks have which strong<br /> charge just that there is at least one of each primary colour.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">An atom is electrically neutral because it has a balance of positively charged protons in the nucleus and negatively charged electrons surrounding it; a helium nucleus contains two protons and has two electrons surrounding it which means the electric charge is +2 -2 = 0. In the same vein a proton has to be strong force neutral, it must have a balance of the three strong charges; composed from one green charged quark, one red charged quark, and one blue charged quark. Which of the two up or one down quarks is charged with each colour doesn’t matter - the fact is just that we need one of each to make a stable proton. </span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><span style="-webkit-text-stroke-width: initial;">We can then say that the stable proton is white as green plus blue plus red light equals white. The same rules applies for all other particles made in a similar way, the group of particles known as Baryons. Almost any combinations of three quarks can create a Baryon as long as the Baryon is white in strong charge. Remember I am in no way saying that quarks have colour in the traditional sense, because we cannot see quarks in the traditional sense - assigning them a colour is an analogy that fits the way in which the strong force behaves. Below are diagrams showing Murray Gell-Mann's mathematical idea of explaining experimental data of the time, called the Eightfold way. These two diagrams</span><span style="-webkit-text-stroke-width: initial;"> shows all ways you can create Baryons made from up, down, and strange quark building blocks. The particle made of three strange quarks at the very bottom of the second diagram (Baryon Decuplet) is the </span><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: Helvetica;">Ω</span><span style="-webkit-text-stroke-color: rgb(0, 0, 0); -webkit-text-stroke-width: initial; font-family: Helvetica;"><sup>- </sup></span><span style="-webkit-text-stroke-width: initial; font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">particle that Gell-Mann predicted to exist and won him the nobel prize in 1968 after it was discovered.</span></span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUVLGuNjE8WMWxueLmvrKqBzT33AdSdMgPAawnt-umFDZwDQ79ryYz3_NDASfh5NRE4sXfqWfH-0PmMG0UXbP3qBaZMoUFh4x1HxKNkFxFD_qDutW-fOS5PaI6Kgym0D-w_fuGWUaopHM/s1600/BaryonOctet.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="444" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUVLGuNjE8WMWxueLmvrKqBzT33AdSdMgPAawnt-umFDZwDQ79ryYz3_NDASfh5NRE4sXfqWfH-0PmMG0UXbP3qBaZMoUFh4x1HxKNkFxFD_qDutW-fOS5PaI6Kgym0D-w_fuGWUaopHM/s640/BaryonOctet.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The Baryon Octet: The central combination of quarks manifests itself as two distinct type of particle so </span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The Baryon Decuplet: Show more possibilities of Baryon using the up, down, and strange quarks. In the 60's the heaviest quark known of was the strange quark.</span></td></tr>
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<i><a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-3-antiquarks-and-anti.html">Next post: Antiparticles and the rule of Two; how antimatter adds more creativity to the way composite particles can be made.</a></i></div>
Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com2tag:blogger.com,1999:blog-6334446934922301536.post-62398262287127590952015-07-16T08:30:00.000+01:002015-07-19T22:51:24.719+01:00Pentaquark Series 1: What Are Quarks?<i>This is the first in a series of posts I will release over the next two weeks aimed at covering the physics behind Pentaquarks, the history of "discovery", and the implications of the latest results from LHCb. We start off today by first answering the question:</i><br />
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">What Are Quarks?</span></h2>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Quarks are building blocks that cannot be broken into <br />smaller things.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Quarks are: a group of fundamental particles that are indivisible, meaning that they cannot be broken into smaller pieces. They are building blocks that combine in groups to make up a whole zoo of other (composite) particles. They were first thought up by physicists Murray Gell-Mann and George Zweig while attempting to mathematically explain the vast array of new particles popping up in experiments throughout the 1950’s and 1960’s. </span><br />
<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Debris that results from smashing protons and protons into each other was seen in experiments to be a whole lot messier than debris from two electrons colliding headlong. Gell-Mann and others reasoned that this would happen if the proton were not a single entity like the electron but instead, like a bag of groceries, containing multiple particles within itself. </span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The menagerie of particles being discovered each week at particle accelerators could, in Gell-Manns model, all be explained as different composites of just a few types of truly fundamental particles. The multiple that seemed to fit the data in most cases was three and Gell-Mann got the spelling for his 'kwork' from a passage in James Joyce’s ‘Fineganns Wake’ - <i>“Three quarks for Muster Mark”</i>. Proof of Gell-Mann’s model came when a particle he predicted in 1962 to exist (which he called Ω<sup>-</sup>) was seen at an experiment at Brookhaven National Lab in the US in 1964. Gell-Mann received the Nobel Prize in Physics in 1969 for this work which was the birth of the quark.</span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">We know today that the proton is made up from three quarks; two up quarks and one down quark. The naming of ‘up’ and ‘down’ shows that some poetry disappeared in naming the individual types of quark! The up and down quarks have the lightest mass of all of the quarks (they would weigh the least if we could practically weigh something so small!). The fact they are so light also means they are the most stable of all of the quarks. Experiment has shown us that the heavier a particle is the shorter its lifespan. Just like high fashion models, particles are constantly wanting to become as light as possible. </span></div>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Protons and neutrons are each made from three quark building blocks.</span></td></tr>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">A neutron particle is also composed of a grouping of three quarks; one up quark and two down. The lifetime of a neutron sitting by itself is limited because although moderately stable (metastable) it knows it can still become a lighter proton. The change from neutron to proton (plus electron and neutrino) is known as radioactive beta decay. Experiments around the world have been looking closely at protons to see if they, like the neutron, change into something lighter. To date not a single experiment has seen a proton decay into anything else which suggests that the proton is immortal and certainly the most stable composite particle we know of.</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNGeqPD6x7qPWp1jP0YtvFqOseWqnzHiuPEfmqOrpE8g6UnZ7FewrtWEAMi3iTCC7qp5F5ReyTC7XLwIvul7_-a-MqAGc6FowdNStTRYun-qhyphenhyphendU3iUnAHgbFWdaSbkeDOPxleODb1pVA/s1600/Quarks.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="317" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNGeqPD6x7qPWp1jP0YtvFqOseWqnzHiuPEfmqOrpE8g6UnZ7FewrtWEAMi3iTCC7qp5F5ReyTC7XLwIvul7_-a-MqAGc6FowdNStTRYun-qhyphenhyphendU3iUnAHgbFWdaSbkeDOPxleODb1pVA/s400/Quarks.png" width="400" /></a><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">The up and down quarks are part of what is known as the first generation of fundamental particles. For reasons which we do not know Nature has presented us with two more generations. The only difference between particles in each generation is their mass. Generation 1 particles are lightest, with generation 2 particles heavier than 1 but in turn lighter than generation 3, which are the heaviest. All of the other properties of the particles, they way they feel forces, seem to remain the same; E.g. their electric charge. The heavier versions of the down quark in generation 2 and 3 are called strange quark and bottom quark. The heavier versions of the up quark are called the charm quark in generation 2 and top quark in generation 3. </span></div>
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<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Heavy particles are made in particle accelerators like the LHC thanks to Einstein’s most famous equation E=mc<sup>2</sup> which tells us that mass of new particles (m) can be created from lots of energy (E). The heavier the particles we want to make the higher in energy we have to accelerate protons to in our accelerator before smashing them together. Remember I said heavy particles are unstable, it turns out that the heavier they get the more unstable they become which means any heavy particle made with quarks from generations 2 or 3 are usually not around for very long.</span><br />
<span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"><br /></span><span style="font-family: Times, Times New Roman, serif;"><i><a href="http://neutrinoscience.blogspot.co.uk/2015/07/pentaquark-series-rule-of-three.html">Next Post: Rule of Three - Why are there not a different number of quarks in protons and other similar particles?</a></i></span></div>
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Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com4tag:blogger.com,1999:blog-6334446934922301536.post-36424632052598629302014-02-17T17:38:00.001+00:002014-02-18T10:25:31.957+00:00Neutrino Experiments and the UKA <a href="http://www.bbc.co.uk/news/science-environment-26017957">BBC news story</a> surfaced last week stating a UK backing of the next
generation of long baseline neutrino experiment in the US. While there is a hope that
some UK institutions will receive funding for involvement in the
project, there is also UK hope of funding for other similar projects. Right now funding is not certain. Here I want to state the facts as they exist and will explain a little about what these experiments are.<br />
<br />
Neutrino physicists in the UK are
at right now is the proposal stage for these next generation projects. In late September last year all physicists with an interest in these types of project jointly submitted a Statement Of Interest (SOI) to the <a href="http://www.stfc.ac.uk/">Science and Technology Facilities Council (STFC)</a>. In the document the exciting scientific opportunities of three projects (LBNE, Hyper Kamiokande and CHIPS) were discussed. The document was very well received and STFC (who provide UK funding for UK particle physics amongst other sciences) invited all three groups to submit formal proposals.<br />
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<tr><td class="tr-caption" style="text-align: center;">The proposed Hyper Kamiokande neutrino detector.</td></tr>
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The formal proposals are to apply for three year of funding for a preparatory phases of research and design into each proposed experiment. As I write this blog post these proposals are also still being written. Until they are completed and submitted to STFC then there cannot be any decision made as to which experiment(s) the UK will fund participation in. Submission of these formal proposals is due early this year. Once all three proposals are submitted there will be further
deliberation on the UKs involvement in these next generation of neutrino
experiments. Until then University groups throughout the UK are using
their expertise to shape the way in which all three of these projects
progress.<br />
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It is worth noting here also that none of the three projects are European
based. Both LBNE and CHIPS are to be hosted in the US while Hyper
Kamiokande is located in Japan. Last year CERN decided not to commit to a large
scale projects such as these because of the continuation and upgrade of the Large Hadron Collider as well as other commitments to particle physics in Europe. European collaborators, including
those from the UK, will however play a key role in these US and/or Japanese based experiments.<br />
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My sincere hope is that the UK can find funding to participate in more than one of the proposed projects. Many have acknowledged that the complementarity of the experiments is an essential part in achieving the stated scientific goals. Individually each experiment brings something common and also different to the table. In combination these experiments will allow the scientific goals of the neutrino physics community to be achieved much faster and to greater accuracy. But for now we have to wait as it will still be some time yet before a decision is made.<br />
<h4>
What is a long baseline neutrino experiment? (What do each of the three experiments have in common?)</h4>
Long baseline neutrino experiments use <a href="http://neutrinoscience.blogspot.co.uk/2011/01/birth-death-and-neutrino-beams.html">man made beams of neutrino</a> particles to understand a natural phenomenon known as <a href="http://neutrinoscience.blogspot.co.uk/2011/06/coming-at-it-from-all-angles-part-1.html">neutrino oscillations</a>. In gaining a detailed picture of how these neutrinos oscillate it is thought that we can answer a long standing question in the scientific creation story of the Universe; <a href="http://neutrinoscience.blogspot.co.uk/2010/11/symmetries-and-birth-of-universe.html">where did all of the raw materials for the Universe come from?</a><br />
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<h4>
What are the differences between the three experiments?</h4>
There are a list of differences. Firstly the experiments will each see a different neutrino beam* which means a different energies of neutrino they are seeing. Secondly they are located at different distances. This is important because a over a long journey one must take into account effects that the Earth has on neutrino oscillation. Thirdly the experiments will be sampling their neutrino beams using different detector technologies. Some will be using the tried and tested technology of <a href="http://neutrinoscience.blogspot.co.uk/2010/11/faster-than-light.html">water Cherenkov</a> and others a highly sophisticated new technology involving liquid argon.<br />
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These differences mean that although the experiments are trying to measure the same things they are approaching them from different angles. It would be like trying to build up a three dimensional picture of an object from a selection of 2D photographs. One experiment gives you one angle but an array of lighting conditions. From these pictures you could get an indication of what the 3D object truly looks like. But, if you had photographs from another angle, also in different lighting conditions, your 3D picture would really take shape. The more angles you have you had the quicker you could understand the true 3D shape of the object and the more accurate a 3D picture you could construct.<br />
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*Although CHIPS and LBNE will both see neutrinos coming from Fermilab they are at different angles from the centre of the neutrino beam.Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com1tag:blogger.com,1999:blog-6334446934922301536.post-43445696376994304362014-02-11T17:27:00.001+00:002014-02-12T09:36:08.359+00:00NOvA See Neutrinos From A DistanceToday the NOvA experiment saw its first neutrino interaction at the far detector from a <a href="http://neutrinoscience.blogspot.co.uk/2011/01/birth-death-and-neutrino-beams.html">man made neutrino beam</a> that was created 810km away. This is a landmark that means there are now two games in town when it comes to understanding the bizarre phenomenon of <a href="http://neutrinoscience.blogspot.co.uk/2011/06/coming-at-it-from-all-angles-part-1.html">neutrino oscillations</a>.<br />
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When completed the far detector will weigh in at a huge 15,000 tonnes - over twice the weight of the Eiffel Tower in Paris! Right now it is well on its way to completion with most of the detector block, who each weigh around 190 tonnes, installed. The video below shows a timelapse video of what it takes to get just one of these layers in place.<br />
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<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/gFpK00WJl90?feature=player_embedded' frameborder='0'></iframe></div>
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Huge congratulations to the NOvA team for their first neutrino sighting, which is shown below. The beam in this picture is going from left to right through the detector. With nothing seen entering from the left, because neutrinos have no electric charge, there is suddenly a shower of electrically charge particles. The electrically charged particles come from a neutrino in the beam interacting with one of the atoms that make up the detector. Light is produced from the charged particles, ehich is detected by electronics and information fed to computers. What you see below is a reconstruction of this information. <br />
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<a href="http://www.fnal.gov/pub/presspass/press_releases/2014/images/NOvA-201402/NOvA-events-side-view-mr.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://www.fnal.gov/pub/presspass/press_releases/2014/images/NOvA-201402/NOvA-events-side-view-mr.jpg" height="105" width="400" /></a></div>
Things are getting exciting in neutrino physics. With the <a href="http://neutrinoscience.blogspot.co.uk/2010/11/identity-crisis-in-japan.html">T2K</a><a href="http://neutrinoscience.blogspot.co.uk/2010/11/identity-crisis-in-japan.html"> experiment</a> continuing to understand neutrinos over shorter distances in Japan it is hoped that the complimentary measurements to come from NOvA with bring about great leaps in our understanding of neutrinos. Who knows, maybe they will finally reveal secrets which will answer some of the <a href="http://neutrinoscience.blogspot.co.uk/2010/11/symmetries-and-birth-of-universe.html">biggest questions in science today</a>.<br />
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<a href="http://www.fnal.gov/pub/presspass/press_releases/2014/NOvA-20140211.html">Press release and more information about NOvA.</a><br />
<br />Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com1tag:blogger.com,1999:blog-6334446934922301536.post-45219640541409301372012-04-12T12:01:00.003+01:002012-04-12T12:01:43.560+01:00RENO Update<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Today RENO Updated their <a href="http://arxiv.org/abs/1204.0626">paper on arXiv</a> with an updated data analysis reducing their confidence on the value of the third and final characteristic of the neutrino. Despite the enhanced uncertainty they still present evidence of measuring this piece of the neutrinos character, but now with slightly less confidence than the <a href="http://neutrinoscience.blogspot.jp/2012/03/daya-bay-reactors-and-neutrinos.html">Daya Bay</a> experiment quote.</span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">This characteristic is measured by looking for electron antineutrinos disappearing on a short journey of just over a kilometre from a nuclear reactor to neutrino detector. Both RENO and Daya bay do this by having a near detectors close to the nuclear reactors, measuring the number of neutrinos being produced, and then far detectors >1km away looking to see if they see the same number. It is not just the distance they travel but in fact the distance divided by the energy of the neutrino, L/E. So for a fixed travel distance, as we have with detectors stuck in place, we look for different energy neutrinos disappearing from near to far detector. In the plot below, which is from RENO's latest paper, we see less neutrinos at certain energies in the far detector than we do in the near, Far/Near ratio less than 1.</span><br />
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<tr><td class="tr-caption" style="text-align: center;">Neutrinos disappearing at certain L/E tells us the value of theta-13.</td></tr>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><br /></span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The characteristic is essentially just a number which we call theta-13. The larger the number the more electron anti-neutrinos at certain energies decide to disappear over this short journey. So to understand the exact number making this decision it is importnat to understand how many neutrinos you expect and how many impostors you might see pretending to be neutrinos from the nuclear reactor.</span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><br /></span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Their updated analysis differs from the original in 2 ways:</span><br />
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<li><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Backgrounds, or non reactor neutrino events. These come primarily from the beta radioactive decay of Lithium (<sup>9</sup>Li) and Helium (<sup>8</sup>He). The number and energy (or spectrum) of such fake events have to be well understood so you know that what you are looking at are indeed neutrinos from the nuclear reactor. The number of neutrinos at each energy changed slightly with further understanding of these beta decay emitters and this knowledge is used in the updated analysis.</span></li>
<li><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">They present enhanced errors to account for the uncertainty in the overall number of neutrinos coming from the nuclear reactors which are their source of the particles. A greater uncertainty in the number of neutrinos expected means a larger error on the characteristic they measure.</span></li>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">This effects the result, value of theta-13, which they present in two ways:</span></div>
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<li><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The value of the theta-13 is higher due to the change in background events at certain energies. More background means that of the observed events seen less are from reactor born neutrinos. This means therefore that more of the reactor neutrinos have disappeared, hence a larger theta-13 value is presented with this update.</span></li>
<li><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The increased uncertainty of neutrino number at all energies directly relates to a larger error on the final theta-13 value measured. This decreases the confidence of the new theta-13 value, but still leaves the confidence high enough to claim a measurement.</span></li>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Either way a value of theta-13 as measured by RENO and Daya Bay heralds a new era in neutrino physics - it is about to get very interesting indeed! </span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><br /></span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">With all this talk of neutrino characteristics and theta-13 you may be wondering exactly what we are looking at these neutrinos doing and what these numbers mean... to learn more follow my series <a href="http://neutrinoscience.blogspot.jp/2011/06/coming-at-it-from-all-angles-part-1.html">"Coming at it From All Angles"</a> which I will, in the coming days I promise, complete and arrive at this third and final characteristic common between neutrino and anti neutrino.</span>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com2tag:blogger.com,1999:blog-6334446934922301536.post-8181217054057378322012-04-03T15:35:00.001+01:002012-04-17T03:42:01.384+01:00RENO Confirms the Daya Bay ResultThis morning the RENO experiment based in South Korea confirmed the results published by the Daya Bay experiment with larger certainty. RENO announced that is has seen evidence of electron antineutrinos from nuclear reactors disappearing, by changing into other neutrino types, over a very short distance. This is the same behavior seen and <a href="http://neutrinoscience.blogspot.co.uk/2012/03/daya-bay-reactors-and-neutrinos.html">announced by Daya Bay</a> about a month ago.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjamXxKvB2PYGGjBF3dzCWofUg-aXtApu4VRoOnrZ3rIKTXIe692gX5qcF5HIOYUxjCRH6PkxHRQU2AP2M-TBcwPcA29E4tC3OmrBd25poZ1uoLGeB9RhlkuuAx6xJQXE0ciBYpywV3Lc4/s1600/RENO.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="211" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjamXxKvB2PYGGjBF3dzCWofUg-aXtApu4VRoOnrZ3rIKTXIe692gX5qcF5HIOYUxjCRH6PkxHRQU2AP2M-TBcwPcA29E4tC3OmrBd25poZ1uoLGeB9RhlkuuAx6xJQXE0ciBYpywV3Lc4/s320/RENO.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A RENO detector.</td></tr>
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The character of the neutrino as seen by these experiments now suggests that experiments like T2K and NOvA will be able to start measuring the imbalance between matter and antimatter. Measuring this imbalance is key to understanding the creation of the Universe. These experiments will fire beams of neutrinos and antineutrinos at different times and look for any differences in their behaviour. It is thought that the difference prefers matter and is the reason there is lots of it about to form the Universe in which we live.</div>
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Want to know more about the experiments and physics - check my Daya Bay post <a href="http://neutrinoscience.blogspot.co.uk/2012/03/daya-bay-reactors-and-neutrinos.html">here</a>.<br />
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*UPDATE* - RENO updated their results. For more on this update and the experimental techniques see this post <a href="http://neutrinoscience.blogspot.com/2012/04/reno-update.html">here</a>.</div>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com1tag:blogger.com,1999:blog-6334446934922301536.post-75570998643863032232012-03-08T11:28:00.000+00:002012-04-12T10:57:38.217+01:00Daya Bay, Reactors and Neutrinos<div>
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The Daya Bay experiment located in China has brought us <a href="http://newscenter.lbl.gov/news-releases/2012/03/07/daya-bay-first-results/">one step closer</a> to understanding the ghostly neutrino and therefore the secrets they are thought to hold. They have for the first time seen electron antineutrinos from nuclear reactors changing into other types of antineutrino. So what does this all mean?</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><u>Experimenting with Neutrinos</u></span></div>
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<tr><td style="text-align: center;"><a href="http://www.hk-phy.org/energy/power/nuclear_phy/images/daya_bay.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" src="http://www.hk-phy.org/energy/power/nuclear_phy/images/daya_bay.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The Guangdong Daya Bay Nuclear Power Station, <br />
where neutrinos are born.</td></tr>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">After the idea of dropping atomic bombs was deemed to be a bit extreme, it was in fission reactions from nuclear reactors that gave us the first glimpse of the intriguing (anti)neutrino in 1956. Ever since then nuclear power stations have been a popular source of electron antineutrinos for experiments. </span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Alongside nuclear reactors scientists also make muon-like neutrinos using large particle accelerators, similar to the Large Hadron Collider at CERN. Natural sources from the Sun and Earths atmosphere have also been used by experiments.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">This work is building upon years of research into understanding the very secretive neutrino. The Double CHOOZ and T2K experiments have both hinted that the change Daya Bay have seen is indeed a real possibility. The result presented by Daya Bay agrees well with these previous hints. It is exciting because it brings us one step closer to understanding the inner workings and quite possibly the creation of the Universe in which we live.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><u>The Changing Neutrino</u></span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">A(n) (anti)neutrino can have three personalities; electron-like, muon-like or tau-like. The personality of the neutrino is known to be a fickle thing that can change as it travels from birth until it shows itself by finally interacting with the Universe around it. The way in which their personality changes is understood and determined by rigid maths but the exact speed and magnitudes to which the personalities change is fixed by Nature. The only way to determine these speeds and magnitudes is by experimenting with neutrinos and measuring the numbers Nature has chosen. </span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHpZbwS_kbYWAb8OX6i8EWSUmZV76BSs58wpHZBEXl-f_r9LH3fI2mWiog40jnMTyUC6NJ1wu2cYv0OODphEnIhy-JnannnhWCsansgoYQw_HKjJubwVDu5rgy5781Y_qR6vjHzi50_mE/s1600/ConfusedNeutrino.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="304" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHpZbwS_kbYWAb8OX6i8EWSUmZV76BSs58wpHZBEXl-f_r9LH3fI2mWiog40jnMTyUC6NJ1wu2cYv0OODphEnIhy-JnannnhWCsansgoYQw_HKjJubwVDu5rgy5781Y_qR6vjHzi50_mE/s320/ConfusedNeutrino.png" width="320" /></a></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Two numbers determine the speed of personality change and these depend on the difference in the mass of three neutrinos. These numbers have been measured and are being understood with greater and greater accuracy using different personalities of neutrino.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Three numbers need to be measured to understand the magnitude to which personalities change. Two of these magnitudes have proven to be large, because of their size they have been relatively easy to measure. Again experimenting with different neutrino personalities continues to improve the accuracy to which these numbers are known.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The third and final magnitude, however, has proven very challenging because it is very very small, especially when compared to the other two. Hints were published by the CHOOZ and <a href="http://neutrinoscience.blogspot.com/2011/06/hello-there-electron-neutrino.html">T2K</a> experiments that this magnitude could be just a little greater than zero. Today the Daya Bay experiment announced that that they had seen enough evidence to claim a first measurement of this final number.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><u>So Why Measure These Numbers?</u></span></div>
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<a href="http://pprc.qmul.ac.uk/~still/homepage/Matter_and_Anti-Matter_files/javascript-void%28img9.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><img alt="" border="0" src="http://pprc.qmul.ac.uk/~still/homepage/Matter_and_Anti-Matter_files/javascript-void%28img9.jpg" style="border-bottom-style: none; border-color: initial; border-color: initial; border-left-style: none; border-right-style: none; border-top-style: none; border-width: initial; border-width: initial; height: 300px; width: 248px;" /></span></a><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The short answer is because it allows us to measure one very special number, one that can tell us about the creation of the Universe. The longer answer to lies in the far mists of time, back when the Universe was less that seconds old and still just pure energy. <span class="Apple-style-span" style="-webkit-text-size-adjust: none; line-height: 16px;">As Einstein wrote in his most famous equation E=mc</span><span class="Apple-style-span" style="-webkit-text-size-adjust: none; line-height: 16px;"><span class="style_1" style="font-style: normal; font-weight: 400; line-height: 16px; vertical-align: 4px;">2 ; </span></span><span class="Apple-style-span" style="-webkit-text-size-adjust: none; line-height: 16px;">from energy, E, you can create mass, m. Particle physicists such as myself use this principle to create a menagerie of things in the smallest realm of nature. When we perform our experiments we create matter, the stuff in the atoms that make the planets, stars and entire visible Universe in which we live. We also create equal amounts of something called anti-matter.</span></span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Anti-matter is a mirrored reflection of the constituents of atoms, exactly their opposite in every way, except they have the same mass. If one were upwards the other would be downwards, one hot then the other cold. In the same way a movement up can cancel down and heat can eliminate the cold, matter cancels anti-matter. When the two meet they cease to exist and form pure energy, which is usually light. So the light which gave birth to the matter and anti-matter lives once more. </span></div>
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<a href="http://apod.nasa.gov/apod/image/0509/sky_wmap_big.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="160" src="http://apod.nasa.gov/apod/image/0509/sky_wmap_big.jpg" width="320" /></a><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">According to current experiments this cycle of destruction and creation would continue, until all of the light had so little energy that it could not produce the lightest mass matter and antimatter anymore. This would leave the Universe today as a collection of nothing but microwaves - similar to the picture of the microwave universe take by the WMAP satellite (left). No atoms could form, no stars would burn and no planets would exist to nurture fragile complex life. A good analogy would be heating a room and cooling with equal power simultaneously. There would be warm and cold patches dotted around but after some time the net effect would be zero, the room would be exactly the same temperature as before.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><span class="Apple-style-span">So how are we here? Well r</span>aw material for all we observe, and continue to discover, was created in the first few seconds shortly after the Big Bang of energy. The fuel for stars, the very first matter, had to have been created in larger amounts than the mirror counterpart anti-matter. With the trillions and trillions of times that the energy-mass-energy cycle was spinning every fraction of a second, it only needed to be a rare occurrence that more matter was produced.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Over production of matter came in collisions between the smallest possible building blocks, the elementary particles. Bit by bit rare extra matter creating interactions produced the fuel for the first stars which then proceeded to create the Universe today. Without those rare interactions nothing would exist.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">To understand these rare interactions and the interplay between matter and antimatter is to determine the origin of the material Universe as we see it. To see something as rare as the extra matter creating interactions scientists study billions upon billions of interactions or the way in which properties of matter and antimatter differ. </span></div>
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<a href="http://pprc.qmul.ac.uk/~still/homepage/Media/Rotating_Square.gif" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img alt="" border="0" class="inline-block" src="http://pprc.qmul.ac.uk/~still/homepage/Media/Rotating_Square.gif" style="border-bottom-style: none; border-color: initial; border-left-style: none; border-right-style: none; border-top-style: none; border-width: initial; display: inline-block; height: 244px; margin-top: 12px; position: relative; vertical-align: baseline; width: 244px;" /></a><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><span class="Apple-style-span" style="font-family: Times; font-weight: normal; line-height: 16px;"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">This bias towards matter can be explained in the language of science, mathematics, with a slight imbalance in the symmetry between matter and anti-matter. A symmetry occurs where we can manipulate something and return to the same picture we started with; for example if we rotate a square 90 degrees in either direction we get back to the same square, this we call rotational symmetry. Just the same we can reflect a picture of a square in a mirror and the reflected square looks identical to the original, this is reflectional symmetry. We use manipulations such as reflection and rotation in our mathematics to do this with our picture of the Universe.</span><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"></span></span><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"></span></span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Let us take a simplified picture of the Universe in the form of a wood cut tessellation of flying fish by the artist MC Escher (below). This is essentially our picture of the Universe as we measure it in our experiments each day, equal amounts of matter (white fish) and anti-matter (black fish). What we will now do is manipulate this picture and hopefully get back to exactly the same, to find a symmetry. We do this from left to right in the picture below.</span></div>
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<a href="http://bit.ly/akcMQQ" style="margin-left: auto; margin-right: auto;"><img alt="" src="http://pprc.qmul.ac.uk/~still/homepage/Matter_and_Anti-Matter_files/AllEscher.png" style="border-bottom-style: none; border-color: initial; border-color: initial; border-left-style: none; border-right-style: none; border-top-style: none; border-width: initial; border-width: initial; height: 183px; width: 692px;" /></a></div>
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Tessellation by <a href="http://www.mcescher.com/">M.C. Escher</a>, modified by me idea <a href="http://www.blogger.com/"><span id="goog_219160842"></span>© Ben Still<span id="goog_219160843"></span></a></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">First we take a negative of the picture, turning all that is black to white and visa versa. The picture now looks nothing like the original so lets think of other manipulations we can perform. Lets turn the picture over, rotating it so that everything on the left is now on the right and right on the left. OK, still not back to the original. I remember the black fish in the middle pointing upward so lets flip the picture again, this time everything on the bottom to the top and top to bottom.</span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">There we have it. The same picture we started with... well almost. You have probably noticed a small difference in the eyes of the fish. This is an exaggerated version of what occurs in our Universe between matter and antimatter. This small difference, or asymmetry as we call it, is present in Nature but at a much smaller level than is shown here by the eyes of the fish. In fact if we were to represent the amount thought to be present in Nature then it would effect about one pixel in this picture - the worst spot the difference puzzle ever! But it is exactly this difference that we are searching for and in the T2K experiment we hope to do this using the most ghostly of natures building blocks, the neutrino.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">The technical name for this asymmetry is CP violation, which stand for Charge-Parity violation. Charge is the first manipulation we performed by taking the negative of the picture, effectively turning all matter to anti-matter and visa versa. Parity is a fancy word for directions in space. So the two changes left to right and up to down are the parity changes. The symmetry between matter and anti-matter is therefore called CP symmetry and as I mention the difference, or asymmetry, is a violation of this.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><u>So What now?</u></span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">First we need to measure this third and final magnitude to accuracy so we are confident </span><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">we understand the personality changes of the neutrino. We also need to measure the number using different methods to confirm that this is indeed Natures choosing and not something to do with the experiment itself. </span></div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDK1wUH-dTXHPpxs8M1BtbY1RUoNH1f-c66Yz1wjZnXJct8SnrdI6xHAuA4NBJoIR6ev6QN-yEYmoupr4fUema6j_hoRvqQrxNe8kp05imTpHdqIUQMmCqkCMcHCV2Y3Y5-AHWRj08TX0/s1600/PH20-water-withboat-apr23-wm_small.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="214" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDK1wUH-dTXHPpxs8M1BtbY1RUoNH1f-c66Yz1wjZnXJct8SnrdI6xHAuA4NBJoIR6ev6QN-yEYmoupr4fUema6j_hoRvqQrxNe8kp05imTpHdqIUQMmCqkCMcHCV2Y3Y5-AHWRj08TX0/s320/PH20-water-withboat-apr23-wm_small.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">T2K will confirm Daya Bays results in its own unique way.</td></tr>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Then come the exciting part - we start to look at the behaviour of neutrinos (matter) and antineutrinos (antimatter) with a confidence that any difference seenis due to CP violation and not their fickle personality. This is where the neutrinos secrets could explain the creation of the Universe. This cannot be done with reactor experiments like Daya Bay or Double CHOOZ because they have just antineutrinos. Instead it falls to the experiments which use neutrinos created by particle accelerators such as the T2K or the upcoming NOvA experiments. These experiments can fire either neutrinos or anti-neutrinos and see subtle difference in the way they behave.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">This result is a massive mile stone in understanding Nature, but the game is most definitely afoot.</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><a href="http://newscenter.lbl.gov/news-releases/2012/03/07/daya-bay-first-results/">Daya Bay Berkley Press Release</a> </span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><a href="http://arxiv.org/pdf/1203.1669v2.pdf">Paper on arXiv</a></span></div>
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</div>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-50420183065815941812012-02-23T11:56:00.002+00:002012-02-23T12:05:14.636+00:00Faster Than Light or Faulty Wiring?CERN today released a <a href="http://bit.ly/Ab65Lr">statement</a> that the team working on the OPERA experiment have found two possible sources of error which could alter the faster than light neutrino statement <a href="http://neutrinoscience.blogspot.com/2011/09/arriving-fashionable-late-for-party.html">announced in back in September</a>. Both error sources are to be investigated in depth with results expected in May.<br />
<br />
<a href="http://static.ddmcdn.com/gif/top-5-myths-about-google3.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="233" src="http://static.ddmcdn.com/gif/top-5-myths-about-google3.jpg" width="320" /></a>The first source of error is a piece of electronics which plays a key role in making sure the time on the GPS in CERN and at the OPERA detector in Gran Sasso agree. This would lead to an overestimate in the time it took the neutrino to make the 734km journey making the neutrino seem slower than it really is.<br />
<br />
A loose connection of a fibre optic cable which brings signal from the GPS outside of the Gran Sasso mountain to the timing electronics of the OPERA detector itself. This would lead to an underestimate in the neutrinos journey time, making the neutrino seem faster than it really is.<br />
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OPERA will operate short bullet pulse of neutrinos to investigate these extent and error associated with these two factors. As with everything neutrino, and indeed particle physics, they will have to wait some time to see enough neutrinos to obtain a consistent picture of what is going on. Only this data driven evidence will tell us if these experimental elements can account for the suggested faster than light travel. We wait until May for the results...<br />
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<u>All Hype, No Cigar...</u><br />
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I have to say that the OPERA scientists and the neutrino physics community as a whole have been open, honest and sceptical at every stage in the discussion of faster than light neutrinos. When the faster than light hint was leaked the OPERA experiment had to publish in a timely manner so that all evidence was laid bare, before too much speculation. They stated the results and their understanding of the errors associated in eloquent and honest fashion - asking all in the community to help understand the suggested result.<br />
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After the paper theorists published reams of papers covering many possible explanations for faster than light neutrino travel. This is no surprise as it is their job. Whenever a new and exciting suggestion of the way Nature works is hinted at or unveiled they provide explanations and hopefully additional routes to pin down the exact story behind the result.<br />
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Some experimentalists were equally enthusiastic to make their voice heard, with the ICARUS experiment publishing a note which, if we are honest, brought no new light on the subject. The result they quote in the paper provides the same contradiction as in the OPERA paper itself. The MINOS and T2K experiments, based in the US and Japan respectively, stated that they could not bring any argument of weight to the table at the current time. These experiments did, however, state that they would upgrade electronics and timing systems in a view that with time they would be able to say something of worth on the subject. Both still stand by this statement and hope to produce results in good time.<br />
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Everyone loves a story and the undermining of our current understanding of the Universe is a BIG story. The scale of public interest was, though, like nothing I could have expected. I enjoyed the fact that the word 'neutrino' was suddenly in the public domain - mainly because it usually took a great deal of description in pub conversations. But in some reports I felt the openness and honesty of the paper itself and the scientists in the community was lost or overlooked.<br />
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Some people have already suggested that this was nothing but a PR stunt to gain interest in our field of science and ensure research funding. I hope that this is not a message shared by the majority. I think that at every stage the subject has been treated modestly by the research community.Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com2tag:blogger.com,1999:blog-6334446934922301536.post-91730974982401002382012-02-07T16:50:00.000+00:002012-02-07T16:51:04.936+00:00A T2K Neutrino Journey<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">With all the talk of <a href="http://neutrinoscience.blogspot.com/2011/09/arriving-fashionable-late-for-party.html">faster than light neutrinos</a> I remembered something I wrote for my website but have never posted as a blog post; well here it is with added faster than light calculation and conclusion.</span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">How long does it take to get from J-PARC, where the beam of neutrinos are created, to the Kamioka mine, home of the Super-Kamiokande far detector in the T2K experiment? Below are a few options...</span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><u>Public Transport...</u></span><br />
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Google maps predicts that, despite the brilliant Japanese public transport system, it would require a traveller to take a one hour walk and a total of five different trains!</span></span></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Journey time: <span class="Apple-style-span" style="color: red;">7 hours</span></span></span></div>
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<span style="letter-spacing: 0px;"><u><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">By Car...</span></u></span></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Google maps suggest a drive which takes in a lot of views en-route. After tackling central Tokyo the route takes the driver past KEK, Japans premier particle physics laboratory until the building of J-PARC, where there are still many particle physics experiments taking place and planned in future. The route proceeds to take the driver through the outskirts of Fuji National Park, where one should get great views of Mount Fuji on a clear day. After a long drive through rural Japan we eventually reach Japans western mountain range and the end of our journey.</span></span></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Journey time: <span class="Apple-style-span" style="color: red;">7 hours and 29 mins</span></span></span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><u>By Neutrino...</u></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHpZbwS_kbYWAb8OX6i8EWSUmZV76BSs58wpHZBEXl-f_r9LH3fI2mWiog40jnMTyUC6NJ1wu2cYv0OODphEnIhy-JnannnhWCsansgoYQw_HKjJubwVDu5rgy5781Y_qR6vjHzi50_mE/s1600/ConfusedNeutrino.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="380" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHpZbwS_kbYWAb8OX6i8EWSUmZV76BSs58wpHZBEXl-f_r9LH3fI2mWiog40jnMTyUC6NJ1wu2cYv0OODphEnIhy-JnannnhWCsansgoYQw_HKjJubwVDu5rgy5781Y_qR6vjHzi50_mE/s400/ConfusedNeutrino.png" width="400" /></a></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><span class="Apple-style-span" style="font-size: small;"><span style="letter-spacing: 0px;">Not a very plausible form of transport for Humans, but if we could travel on or alongside the neutrino then the journey would be a whole lot quicker! The neutrino is an extremely light particle, with a mass of the order of 1eV which is equivalent to just 1.78 x 10</span><span style="font: normal normal normal 9.3px/normal 'Helvetica Neue'; letter-spacing: 0px;"><sup>-36</sup></span><span style="font: normal normal normal 13px/normal 'Helvetica Neue'; letter-spacing: 0px;"> </span><span style="letter-spacing: 0px;">kg, 500,000 time lighter than an electron! This extremely small mass allows a neutrino with relatively small energy to travel at almost the speed of light, the fastest speed possible in the universe.</span></span></span></div>
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<span class="Apple-style-span" style="font-size: small;"><span style="letter-spacing: 0px;">The neutrino is also the most ghostly of particles, interacting only by what is know as the weak nuclear force. This is the force which is responsible for much of the nuclear decay we see in large atoms such as Uranium and Plutonium. The key thing is that it’s name doesn’t lie, this force is feeble, in fact it is 100 billion times weaker than the electromagnetic force which determines the chemistry of everything around us. This all means that the neutrino interacts with regular matter, such as the earth through which it travels between J-PARC and Super-K, extremely rarely. In fact the average distance that a neutrino travels before interacting is measured in light years of lead; that’s lead blocks of the order 10</span><span style="font: normal normal normal 9.3px/normal 'Helvetica Neue'; letter-spacing: 0px;"><sup>16</sup></span><span style="letter-spacing: 0px;">m and more! Because of this the neutrino obviously travels in a straight line between J-PARC and Super-K as it does not interact as our other travelers do, such as changing trains or getting stuck in traffic.</span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFfQR7Jw2J49Uzd8FuLKeeCb10akvEZ_lYJpKc7wdGZGBa2roCt0nFKIiCPfP2lsuYp8PUFNk2lE6ienkKE6dWz2YYmaEUp0FtrzhfP_rws8CfkO-hAPxcU7iuMrw8kVCUrznfIdHPV9Y/s1600/T2KOverview1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFfQR7Jw2J49Uzd8FuLKeeCb10akvEZ_lYJpKc7wdGZGBa2roCt0nFKIiCPfP2lsuYp8PUFNk2lE6ienkKE6dWz2YYmaEUp0FtrzhfP_rws8CfkO-hAPxcU7iuMrw8kVCUrznfIdHPV9Y/s1600/T2KOverview1.png" /></a></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-size: small;">If we couple the speed with the direct line of travel you get a much quicker journey time.</span></span></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-size: small;">Journey time: <span class="Apple-style-span" style="color: red;">Less than 1 miilisecond (that’s 1/1000 of a second)</span></span></span></div>
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<span class="Apple-style-span" style="font-size: small;"><span style="letter-spacing: 0px;"><i>distance, d = 295 km; speed of light, c = 299792458 </i></span><span style="letter-spacing: 0px;"><i>m /s; time, t = d / c ~ 0.984 x 10</i></span><span style="font: normal normal normal 9.3px/normal 'Helvetica Neue'; letter-spacing: 0px;"><i><sup>-3</sup></i></span><span style="letter-spacing: 0px;"><i> s </i></span></span></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-size: small;">Because of this fast journey time we need a fast way of telling the Super-K detector that neutrinos are being fired its way, and this is done using GPS signalling - similar to the GPS found in you Sat-Nav system in your car. The times at which the neutrino beam is fired, and the time at which neutrinos are seen in Super-K, are measured in Universal time by receiving signals from GPS satellites .</span></span></div>
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<span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-size: small;">Recently there has been a suggestion in results from the OPERA experiment that neutrinos may <a href="http://neutrinoscience.blogspot.com/2011/09/arriving-fashionable-late-for-party.html">travel faster than light</a>. If we take the value suggested in their paper then the difference in travel time between calculated above would be <span class="Apple-style-span" style="color: red;">24.4 nanoseconds (1/1000,000,000 of a second)</span>. To try and see this tiny time difference there are plans in the pipeline to upgrade the timing systems currently installed on the T2K experiment (and also the MINOS experiment in the US). These upgrades should be performed within the next year but the ghostly nature of the neutrino will mean that we will not have a definitive answer for a few years yet... watch this space!</span></span></div>
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</span>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-46100341335265763212012-01-28T09:05:00.000+00:002012-02-06T10:21:26.282+00:00From Tokai to Kamioka Once More!After the <a href="http://neutrinoscience.blogspot.com/2011/03/earthquake.html">earthquake</a> which hit the East coast of Japan in March of last year the Tokai to Kamioka (T2K) experiment was taken <a href="http://neutrinoscience.blogspot.com/2011/03/earthquake.html">out of action</a>. But, with the hard work and determination of many scientists and engineers, just 10 months on it is almost back to 100% operation and raring to go.<br />
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<tr><td class="tr-caption" style="text-align: center;">The J-PARC Proton Accelerator, courtesy of KEK.</td></tr>
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Many aspects of the experiment that had to be repaired or rebuilt; the largest and most complex element was the proton particle accelerator (pictured left), used to produce the beam of neutrinos. Magnets, used to accelerate and bend the protons in their circular path, had to be aligned together with millimetre accuracy. These protons then had to be focused, with even greater accuracy to hit a target and produce neutrinos (more info <a href="http://bit.ly/NuBlogNuBeam">here</a>). Months of tweaking and fixing and we now have protons producing neutrinos.<br />
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Then there were the detectors, the machines that actually looked for the neutrinos. Because the neutrinos were being fired such a massive distance of 295 km to the West the very far detector, <a href="http://bit.ly/NuBlogSK">Super-Kamiokande</a>, was unscathed by the earthquake. The collection of near detectors (pictured below) were, however a great deal closer at just 280m from the start of the neutrino beam, on the same site as the particle accelerator. Again the effort of many engineers and scientists has resulted in the successful restart of these huge neutrino cameras.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6ZTv3lilrdmJbn4MuOvGz3ebtUuXJsg1-cx03qKzdJ0LJdMLWkpiDnHMapnlIlfjV3oqZDhtBHRC58M50dcLZTMx36nIYMRWgTOTdd5p6l10uFeQdS7_bt69WkdGIBsCps90IAO7tcnY/s1600/DSC00053.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6ZTv3lilrdmJbn4MuOvGz3ebtUuXJsg1-cx03qKzdJ0LJdMLWkpiDnHMapnlIlfjV3oqZDhtBHRC58M50dcLZTMx36nIYMRWgTOTdd5p6l10uFeQdS7_bt69WkdGIBsCps90IAO7tcnY/s400/DSC00053.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The ND280 near detector of the T2K experiment.</td></tr>
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The last piece of the puzzle is the massive bell-like magnetic horns that focus the neutrino beam and removes unwanted anti-neutrinos. Here it is a case of repairing power supplies that provide a massive 250kA of electricity in nanosecond pulses to generate massive magnetic fields. Despite the lack of focus in the beam at both the near and far detectors in the experiment have seen neutrinos! - see below. Although these sightings will not be used for physics they are a very positive sign that T2K is back. Data taking for physics will begin in March 2012 and it won't be long before it starts to excite the community once again with new results.<br />
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Below I show and example of the neutrinos we have seen this month in the ND280 near neutrino detector, also shown is the one fully contained event seen by the Super-Kamiokande far detector.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvjWM3jxzsx7CLb3t14WnrEKNugWjPlWkvofLla7ZAR8Cn-Eni-y6B93YK7fbsOHxjOM6mApsfHeOVk3OPwfLw5Q8uu5ccYE4AkN2uO7a0hbePskoWT5fhQiDLgE8Z_qvYkXUwfwR9cI4/s1600/ND280RunIIIaEvent.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="329" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvjWM3jxzsx7CLb3t14WnrEKNugWjPlWkvofLla7ZAR8Cn-Eni-y6B93YK7fbsOHxjOM6mApsfHeOVk3OPwfLw5Q8uu5ccYE4AkN2uO7a0hbePskoWT5fhQiDLgE8Z_qvYkXUwfwR9cI4/s640/ND280RunIIIaEvent.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A neutrino event in the near detector.<br />
Courtesy of the T2K ND280 collaboration.</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGKG_dUZhZGy5M_aJRPiKTSgPe-hnH9RWfctaeVgRVqTkRHQZdScxqqc3Oe7j4oY1QCZiLesyWE2-DFlHuNvz5kfjMtZz1DFKjUzHTtqYdGxAD1-v5mvwBC6sUQH6XnRo_jfI9YWa-0ZI/s1600/RunIIIaEvent.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="536" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGKG_dUZhZGy5M_aJRPiKTSgPe-hnH9RWfctaeVgRVqTkRHQZdScxqqc3Oe7j4oY1QCZiLesyWE2-DFlHuNvz5kfjMtZz1DFKjUzHTtqYdGxAD1-v5mvwBC6sUQH6XnRo_jfI9YWa-0ZI/s640/RunIIIaEvent.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A fully contained neutrino event in the Super-Kamiokande detector.<br />
Event display courtesy of Kamioka Observatory, ICRR, University of Tokyo</td></tr>
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</div>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-13218873400792491112011-10-01T09:03:00.000+01:002011-10-01T09:04:38.201+01:00Weak Booom!<div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;">
<span style="font-size: small;">Of the large amount of papers that are being put forward for debunking faster than light neutrinos one in particular caught my eye. On Thursday a <a href="http://arxiv.org/abs/1109.6562">paper by Andrew G. Cohen and Sheldon L. Glashow</a> about faster than light neutrinos losing energy rapidly and not making the 730km at superluminal speed. This post pulls together a lot of threads and I link to previous posts in the text to provide the relevant background.</span></div>
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<tr><td style="text-align: center;"><span style="font-size: small;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEGdaxZGxES_XowgbiLJCF-ChkawbmA7IPMI5nTiNzIadYU8Gn9ev_RnrGdv77e8DRfGxvIceKweP0KizycvkBAlFXYwI0SAsI_b9BKnLrglADFARWiMHbLziv9crJ2PUW1V3IH6E_TBY/s1600/magnet.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEGdaxZGxES_XowgbiLJCF-ChkawbmA7IPMI5nTiNzIadYU8Gn9ev_RnrGdv77e8DRfGxvIceKweP0KizycvkBAlFXYwI0SAsI_b9BKnLrglADFARWiMHbLziv9crJ2PUW1V3IH6E_TBY/s320/magnet.jpg" width="235" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Electromagnetic field</span></td></tr>
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<span style="font-size: small;">The fundamental forces, the rule book for they way the Nature interacts with itself, are communicated to the Universe via things called fields. A good visual example of a field is putting iron filings near a bar magnet - this is the electromagnetic force field made visible. Every particle with an electric charge, e.g. the electron, emits a similar electromagnetic field. These force fields move at the speed limit of the universe - the speed of light. If the <a href="http://neutrinoscience.blogspot.com/2011/01/slow-light.html">speed of light is slowed down</a>, as it is in water or glass, then it is not against the laws of Nature for charged particles to out run light. If this is the case then the charged particles produce flashes of light known as Cherenkov radiation which takes energy away from the particle until it's speed is less than light in water (or some other medium). For more info on Cherenkov light please read <a href="http://neutrinoscience.blogspot.com/2010/11/faster-than-light.html">this previous post</a>.</span></div>
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<span style="font-size: small;">Neutrinos are ghostly as I have said many times and interact rarely with the
Universe. On the rare occasion they do interact it is via the <a href="http://neutrinoscience.blogspot.com/2010/11/may-electroweak-force-be-with-you.html">weak nuclear force</a>. Because the neutrino feels this weak force, Cohen and Glashow put forward the argument that neutrinos would lose energy by a similar process to Cherenkov radiation. Instead of a burst of light however you would get a burst of weak force. Particles of light, photons, are the force carriers of the electromagnetic force and are the things released in Cherenkov radiation. The Z<sup>0</sup> weak force carrier is essentially just a heavy version of the photon and it is this that is released in the burst of weak force.</span></div>
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<span style="font-size: small;">The weak force carriers can't live out in the real world for too long, due their heavy size they are unstable. They quickly die and give birth to matter and anti-matter. When Z<sup>0</sup> dies it can produce pairs of electron and antielectron (positron)<sup>(a)</sup>. In this process the neutrino loses energy until it reaches a lower limit (terminal energy) of about 12.5GeV. The OPERA experiment has however seen neutrinos with energy above this - with average energy about 17.5GeV. Quoting the paper "...observation of neutrinos with energies in excess of 12.5 GeV cannot be reconciled with the claimed superluminal neutrino velocity measurement."</span></div>
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<span style="font-size: small;"><span style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;">(a) The Z0 can also produce neutrino-antineutrino pairs, but the energy constraint here is less marked. Neutrinos can also lose energy by emitting light as well through a complicated self interation of the other weak force carriers the W± but this process is also not too important for this discussion.</span></span>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com12tag:blogger.com,1999:blog-6334446934922301536.post-52057835844929988092011-09-30T07:00:00.000+01:002012-01-29T02:41:06.629+00:00Supernova Neutrinos in 1983 and 1987?<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
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<tr><td class="tr-caption" style="text-align: center;">NOT a good neutrino detector</td></tr>
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Take a look at your thumbnail. This is not some mind game, go on just look. Every second there are over 100 billion neutrinos passing through an area about the size of your thumbnail (~1cm<sup>2</sup>). They pass straight through and continue on their long and lonely cosmic journey. There are trillions passing through your body right now as you read this. But in your lifetime you would be lucky if a single neutrino even noticed you existed, or visa versa. Don't be offended, they are not ignoring you. The neutrino is the shyest of the shy, interacting with the Universe around it on only the rarest of occasions.<br />
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It is possible however for us to catch a rare glimpse of one of these ghostly particles. To increase our chances of seeing a neutrino we require as large an amount of stuff as possible; the more stuff you put in the way of neutrinos the more likely that one will notice it. Massive neutrino detectors are constructed deep underground to shield from other particles coming from cosmic ray interactions the atmosphere. Three massive neutrino detectors saw antineutrinos from SN1987a; the <a href="http://en.wikipedia.org/wiki/Baksan_Neutrino_Observatory">Baksan Underground Scintillation Telescope (Baksan)</a> in Russia, the <a href="http://en.wikipedia.org/wiki/Irvine%E2%80%93Michigan%E2%80%93Brookhaven_%28detector%29">Irvine Michigan Brookhaven (IMB) detector</a> in the US and <a href="http://en.wikipedia.org/wiki/Kamiokande_II#KamiokaNDE">KamiokaNDE</a> in Japan.<br />
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<tr><td class="tr-caption" style="text-align: center;">KamiokaNDE - a much better neutrino detector</td></tr>
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Kamiokande, in its second incarnation in 1987, tried to catch a neutrino in it massive tank of 3000 tonnes of ultra pure water (over 42,000 human bodies worth). Even with all of this stuff in the way Kamiokande II saw around 6 of the trillions upon trillions of neutrinos that passed through it everyday. Imagine their surprise then, when asked by optical astronomers to check their data on 23rd February 1987, they saw a spike of 12 neutrinos in just 12.4 seconds! The spike in number of neutrinos seen was also experienced by the IMB and Baksan experiments who saw 8 and 5 neutrinos each in the same short time (see the graph below). With so many neutrinos seen in such a short space of time there must have been a huge intensity of neutrinos passing through the Earth (10<sup>57</sup>-10<sup>58</sup> neutrinos released in total by the supernova over the few seconds), far greater than that from the Sun and atmosphere combined.<br />
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Intensity of neutrinos equates to intensity of energy, as it is the neutrinos that take energy
away from the supernova. The intensity of neutrinos and energy was calculated and found to agree well with theoretical models. In these models the energy taken away from supernova accounts
for 99% of the total energy emitted. The energy released in forming a neutron star comes primarily from essentially the difference in mass between the normal core and the new neutron star. This is a value that is well constrained. So I argue that if the intensity of neutrinos see just hours before SN1987a accounts for 99% of the theoretically modeled energy released, then there could not have been neutrinos missed 4.14 ±1 years previous.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgy80k2FBmcNwa-14vThYrQwlBYN9spBOAmT73F_gZlu3yQgYZJqGuM44iRcvvMP3s_uQADf18KFr2-dA1iw0-Xbd_5J0vX5eEwNAaSwczDIa6V9z7ngt8WzQ7-09gzv-tSaKGkYQl00_w/s1600/ObsSN1987aNu.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgy80k2FBmcNwa-14vThYrQwlBYN9spBOAmT73F_gZlu3yQgYZJqGuM44iRcvvMP3s_uQADf18KFr2-dA1iw0-Xbd_5J0vX5eEwNAaSwczDIa6V9z7ngt8WzQ7-09gzv-tSaKGkYQl00_w/s400/ObsSN1987aNu.png" width="280" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The SN1987a neutrinos seen. Energy and time since first neutrino. </td><td class="tr-caption" style="text-align: center;"><br /></td></tr>
</tbody></table>
Of the three neutrino observatories that saw antineutrinos from SN1987a, only the IMB and Baksan detectors were active in 1983, both of started operation in 1982. Kamiokande
in Japan, was the largest of the three but did not begin operation until the
second quarter of 1983. As far as I am aware there was no neutrino spike such as that seen in 1987 - after this detection of a supernova in neutrinos was made all historical data was scrutinised and nothing appears in publication.<br />
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The neutrinos seen by these detectors were electron antineutrinos. The reason for this is that the likelihood for electron antineutrinos to interact with the normal stuff around us is far far higher because they have the possibility to interact by inverse beta decay <i>p + anti-ν<sub>e</sub> → n + e<sup>+</sup></i>. One could then make the argument that perhaps the other types of neutrino traveled faster than light and then we missed them 4 years previous because we did not see them. For this argument I point you toward my post on <a href="http://neutrinoscience.blogspot.com/2011/09/supernovas-and-neutrino-types.html">neutrino type</a>.Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com2tag:blogger.com,1999:blog-6334446934922301536.post-18939596697106295812011-09-28T15:29:00.000+01:002012-01-29T02:41:44.838+00:00Not Feeling Very Energetic<div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;">
<span style="font-size: small;">As people have pointed out the neutrinos released in supernova deaths of stars, such as SN1987a, a far less energetic than the neutrino beam used by the OPERA experiment. The energy of neutrinos fired from CERN to the OPERA detector in Gran Sasso, Italy, are of the order 1000 times as energetic as those seen from SN1987a. </span></div>
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<span style="font-size: small;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_IvYHLdSHbTQzw0ZJDSZqUPdcg5DKWHPJCnfp0ODEGAhNIGdMz14dZrILT63BvDm0Jn6t6YyIlQ-13cFYaYoudsUbwhKkB4-ZWQ-IhrhpW_ikXqke4fojbyB4yCTojyZ1xvzK5kY0SRI/s1600/albert-einstein.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="296" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_IvYHLdSHbTQzw0ZJDSZqUPdcg5DKWHPJCnfp0ODEGAhNIGdMz14dZrILT63BvDm0Jn6t6YyIlQ-13cFYaYoudsUbwhKkB4-ZWQ-IhrhpW_ikXqke4fojbyB4yCTojyZ1xvzK5kY0SRI/s320/albert-einstein.jpg" width="320" /></a></span></div>
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<span style="font-size: small;"><u>Old physics: AKA Our Current Understanding of the Universe</u></span></div>
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<span style="font-size: small;">Einstein's theory of relativity assumes that nothing can travel faster than the speed of light, this property is known as Lorentz invariance. It is hard coded into the mathematics and it is the ratio of the squares of the mass and energy that determines how close to the speed of light a particle can travel. The smaller the ratio m<sup>2</sup>/E<sup>2</sup> the closer to the speed of light a particle gets<sup>(a)</sup>.</span></div>
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<span style="font-size: small;">The extremely small mass of the neutrino, the current upper limit is 2eV/c<sup>2 (b)</sup>[1], means that it requires very little energy to travel at amazingly fast speeds. At an energy of 10 of MeV, neutrinos are traveling at 99.999999999998% the speed of light. The difference in speed when we raise the energy of the neutrino to 10GeV is a tiny 0.00000000001998%. If 10MeV (roughly that from SN1987a) and 10GeV (roughly the energy of OPERA) neutrinos were in a race all the way from the large Magellanic cloud, where SN1987a died spectacularly, then the 10GeV neutrinos would arrive just one tenth (0.1) of a second before the 10MeV energy neutrinos. Although the OPERA energy neutrinos would be faster, note that because of Lorentz invariance they would not travel faster than light.</span></div>
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<span style="font-size: small;"><u>New Physics: AKA Pastures New</u></span></div>
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<tr><td style="text-align: center;"><span style="font-size: small;"><a href="http://mi9.com/uploads/landscape/1948/green-field-under-blue-sky_1600x1200_24581.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="240" src="http://mi9.com/uploads/landscape/1948/green-field-under-blue-sky_1600x1200_24581.jpg" width="320" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">The land of theories, where new physics lives.</span></td></tr>
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<span style="font-size: small;">The only way in which this can explain faster than light neutrinos would
be if a new physics, beyond our current understanding, 'switches on' at
high previously unexplored energies. 'Switches on' is a phrase that
theorists like. New physics may exist at scales of energy over the
horizon of our previous experiences as it is in these lands that
theories lie. The GeV energies used by the OPERA is indeed a new frontier in our understanding of the neutrino.</span></div>
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<span style="font-size: small;">I explain in the addendum to my <a href="http://neutrinoscience.blogspot.com/2011/09/arriving-fashionable-late-for-party.html">original blog post on this subject</a>
that the forerunner of theories which allow the neutrino to travel faster than light is that of quantum gravity[2]. Here the neutrinos interact differently than light does with the backdrop of the Universe, the foamy space-time, upon which Nature in played out. This difference in interaction, effectively particles of light - photons - and neutrinos traveling through different subsets of extra dimensions.</span></div>
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<span style="font-size: small;">I would not claim any great knowledge in quantum gravity but I understand that as yet there is no evidence for extra dimensions or the quantum space-time foam talked of. Who knows, if the OPERA results do withstand the rigorous tests and scrutiny they will most certainly be under then it may be the first hint of quantum gravity. Only time, repeat results, and a lot of hard work will tell.</span></div>
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<span style="font-size: small;">Next post I hope to cover the fact that neutrinos might have indeed passed through the Earth 4 years before SN1987a was seen in light.</span></div>
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<span style="font-size: small;">Footnotes</span></div>
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<span style="font-size: small;">(a) It is this ratio that shows us any particle with a (real finite) mass requires infinite energy to reach the speed of light because it is the only way the ratio can get to zero: m / ∞=0</span></div>
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<span style="font-size: small;">(b) eV or electron volts are a measure of energy of the very small. It is the amount of energy you would give an electron particle if you were to accelerate it across an electric potential of one Volt (<a href="http://en.wikipedia.org/wiki/Electronvolt">more info on Wikipedia</a>). From Einstein's E=mc<sup>2</sup> equation we can relate energy and mass and we do so with the units of mass for particles, so we can express small masses in units of eV/c<sup>2</sup>. </span></div>
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<span style="font-size: small;">References</span></div>
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<span style="font-size: small;">[1] <a href="http://pdg.lbl.gov/2010/reviews/rpp2010-rev-neutrino-mixing.pdf">Particle Data Group (PDG) 2011: Neutrino Data </a></span></div>
<span style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">[2]<span class="Apple-style-span"><a href="http://arxiv.org/abs/0805.0253"> Probes of Lorentz Violation in Neutrino Propagation; </a></span><a href="http://arxiv.org/abs/0805.0253"><span class="Apple-style-span">John Ellis, Nicholas Harries, Anselmo Meregaglia, André Rubbia<span style="font-style: normal; font-variant: normal; font-weight: normal; line-height: normal;"> </span>and </span><span class="Apple-style-span">Alexander S. Sakharov</span></a></span><br />
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</div>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com4tag:blogger.com,1999:blog-6334446934922301536.post-34395427751196658842011-09-27T09:43:00.001+01:002011-09-29T09:16:46.788+01:00Supernovas and Neutrino Types<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; font-family: "Helvetica Neue",Arial,Helvetica,sans-serif; text-align: right;"><tbody>
<tr><td style="text-align: center;"><span style="font-size: small;"><a href="http://attemptingmy.finalattempt.net/Site/Blank_files/CupOfTea.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="http://attemptingmy.finalattempt.net/Site/Blank_files/CupOfTea.jpg" width="284" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">A Supernova is like a cup of tea...</span></td></tr>
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<span style="font-size: small;">There has been lots of talk about my <a href="http://neutrinoscience.blogspot.com/2011/09/arriving-fashionable-late-for-party.html">previous post</a> so I would like to follow up with some more comments about Supernova neutrinos. This post covers the comments that the difference between the supernova example I blogged about and OPERA experiment is due to the fact they they are dealing with different types of neutrino.</span><br />
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<span style="font-size: small;">It is true, the neutrinos seen from a supernova such as SN1987a are a different type (technical term is flavour) to that used in OPERA. The difference type cannot, however, be account for the reason we see one type of neutrino traveling faster than the speed of light and not another. I can say this with confidence because neutrinos don't travel as their types but instead as a <a href="http://neutrinoscience.blogspot.com/2011/06/coming-at-it-from-all-angles-part-1.html">mixture of different masses</a>. Each type of neutrino is a different admixture of the same three states of neutrino mass. Because of this the different types of neutrino are inexorably linked - one cannot travel faster than the speed of light with out the other also having the ability to do so. Want to know more about the types of neutrino emitted by a supernova? Then read on...</span></div>
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<span style="font-size: small;">As the core of a supernova collapses (section 1 in the graph below) electrons in atoms are forced to combine with protons - this is called 'neutronification'. The products of this process are neutrons, which form the remnant neutron star, and electron neutrinos. This process takes just a few microseconds produces a sharp pulse (section 2 in the graph). The energy of these neutrinos however were too low for the 1987 neutrino observatories to see.</span></div>
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<span style="font-size: small;"><i>e + p → n + ν<sub>e</sub></i></span></div>
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<span style="font-size: small;"><i>Neutronification (my word of the week!)</i></span></div>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; font-family: "Helvetica Neue",Arial,Helvetica,sans-serif; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><span style="font-size: small;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO_Lq5IT0E8LGaJa5ZUZU_b9jERHZYUbBPHa6_CCdqMnISQ4gjSaSRQuoMm469cjxLvFwrLaZ3VnGMdN3HK7FPZWKCRgeOuYBFA-QGGmLoT0IiyfGI11L1tT4SAOza9Hz_90aLdEVDehg/s1600/SNNeutrinos.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="328" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO_Lq5IT0E8LGaJa5ZUZU_b9jERHZYUbBPHa6_CCdqMnISQ4gjSaSRQuoMm469cjxLvFwrLaZ3VnGMdN3HK7FPZWKCRgeOuYBFA-QGGmLoT0IiyfGI11L1tT4SAOza9Hz_90aLdEVDehg/s400/SNNeutrinos.png" width="400" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The intensity of different types of neutrino as a function of time after collapse.</span></td></tr>
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<span style="font-size: small;">Instead the neutrino observatories saw higher energy neutrinos coming from a longer process called neutrino cooling (sections 3&4 of the graph), which took place over ~10s. When the neutron star forms it is warmer than the surrounding space and cools down to this temperature by emitting radiation; like a cup of tea cooling to room temperature. The radiation from the neutron star however is not light, infrared heat, as in the case of the cup of tea but is instead neutrinos. All types of neutrino; electron, muon and tau, neutrinos and antineutrinos are produced in massive amounts. As they escape they take energy away with them, cooling the neutron star.</span></div>
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<span style="font-size: small;">It is a small subset of these cooling neutrinos that the neutrino observatories saw in 1987. Because of the probability of interaction (something particle physicists call 'cross-section') that the neutrino observatories saw almost all electron antineutrinos (and possibly one electron neutrino). The process that turns one electron antineutrino and a proton into a neutron and a positron (anti-electron), is millions of times more likely than any of the ways in which the other types of neutrino and antineutrino interact. So although all types of neutrino were produced in the neutrino cooling, we only had the opportunity to see electron antineutrinos.</span></div>
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<span style="font-size: small;">I'll try to post again soon covering the difference in energy of the two sets of neutrinos.</span><br />
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<div class="fb-like" data-href="https://www.facebook.com/pages/Neutrino-Blog/194636193880640" data-send="false" data-width="450" data-show-faces="false"></div>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-47638611190151017262011-09-23T03:54:00.006+01:002012-01-29T02:42:36.391+00:00Arriving Fashionably Late for the Party<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">Just a quick post to talk about the latest paper released by the Opera experiment [1] which presents results of neutrinos traveling faster than light in a vacuum. While the debate on systematic errors is going to be a long one I just wanted to play around with some of the number quoted in the paper and relate this to results from an independent neutrino source - a supernova death of a star. Namely supernova (SN) 1987a.</span><br />
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<tr><td style="text-align: center;"><a href="http://www.aao.gov.au/images/image/aat050a.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="http://www.aao.gov.au/images/image/aat050a.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The optical after and before picture of SN1987a (c) AAO</td></tr>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">This was the first supernova to been seen not only in visible light but also in neutrinos (please see <a href="http://neutrinoscience.blogspot.com/2011/01/death-of-giant.html">this post</a> for more on the neutrino signal seen). The difference between seeing neutrinos and the light from the supernova was ~3hours - seen by comparing neutrino observatory and telescope data. We now understand this difference as the journey of the light being impeded by the atmosphere surrounding the dying star.</span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">If the faster than light claim of the Opera paper [1] were to be accepted, as a six standard deviation result would imply, then the difference should have been much much greater. The paper quotes a fractional difference between neutrino speed and that of light of</span><br />
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<i><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;">(v-c)/c = δt/(TOF<sub>c</sub> - δt) = (2.48 ± 0.28 (stat.) ± 0.30 (sys.)) x 10<sup>-5</sup></span></i><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;"><span class="Apple-style-span"><span class="Apple-style-span" style="font-size: small;">Supernova 1987a was a distance of 166,912 ± 10000.1 l</span></span><span class="Apple-style-span"><span class="Apple-style-span" style="font-size: small;">ight years [2] from Earth when it died. Taking these values we can calculate that the time difference between the neutrinos arriving at the neutrino observatories and the telescopes seeing SN1987a would be</span></span></span><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><i>2.48 x 10<sup>-5</sup> x 166912 = 4.14 years</i></span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><br />
</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Combining the errors on the SN1987a distance, systematic and statistical errors of the Opera result we get a value of</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><br />
</span></div>
<div style="font: 12.0px Helvetica; margin: 0.0px 0.0px 0.0px 0.0px;">
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><i>4.14 ± 1 years</i></span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><br />
</span></div>
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">There is no evidence to support that this is the case - as I mentioned the neutrinos were seen just 3 hours before SN1987a was seen by optical telescopes. In this case the neutrinos did not arrive early for the party it was the light that was fashionably late!</span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><br />
</span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><i>*Addendum* There are of course loopholes to this argument, for instance there may be higher order quantum gravity effects which violate Lorentz invariance [3]. Either way the result will be hotly debated - is it an unknown systematic error or some exciting hint at new physics?</i></span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><br />
</span><br />
<a href="http://neutrinoscience.blogspot.com/2011/09/supernovas-and-neutrino-types.html"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Follow up post about supernova and neutrino type.</span></a><br />
<a href="http://neutrinoscience.blogspot.com/2011/09/not-feeling-very-energetic.html"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Follow up post about the difference in neutrino energy. </span></a><br />
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<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">[1] <a href="http://arxiv.org/abs/1109.4897">Measurement of the neutrino velocity with the OPERA detector in the CNGS beam; OPERA collaboration</a> </span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">[2] <a href="http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1991ApJ...380L..23P">Properties of the SN 1987A circumstellar ring and the distance to the Large Magellanic Cloud, Panagia; N., Gilmozzi, R., Macchetto, F., Adorf, H.-M., & Kirshner, R. P.</a></span><br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">[3] <a href="http://arxiv.org/abs/0805.0253">Probes of Lorentz Violation in Neutrino Propagation; </a></span><a href="http://arxiv.org/abs/0805.0253"><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">John Ellis, Nicholas Harries, Anselmo Meregaglia, André Rubbia<span style="font: normal normal normal 8px/normal Times;"> </span>and </span><span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;">Alexander S. Sakharov</span></a><br />
<br />
<br />
<span class="Apple-style-span" style="font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: small;"><a href="http://press.web.cern.ch/press/pressreleases/Releases2011/PR19.11E.html">CERN Press Release here</a></span></div>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com26tag:blogger.com,1999:blog-6334446934922301536.post-42060704367242586302011-07-04T16:29:00.000+01:002011-07-04T16:29:29.515+01:00Coming At It From All Angles - Part 3In <a href="http://neutrinoscience.blogspot.com/2011/06/coming-at-it-from-all-angles-part-2.html">the previous post</a> we found that we can describe how mixed up a neutrino is at birth using three numbers, or angles - and a fourth number which I will keep for a future post (I like to keep you hanging!). But what happens as a neutrino starts its journey through life?<br />
<br />
<u>A Life Less Ordinary</u><br />
<br />
I briefly mentioned that it is the mixture of masses that determines how a neutrinos lives its life between birth and death, when it eventually interacts with the world. The behavior is dictated by a famous equation, which all physics majors will learn at University, the Schrödinger equation. In our system that we set up in the previous post the Schrödinger equation essentially dictates a path which the vector of the neutrino moves along. So a traveling neutrino is equivalent to a vector rotating around the zero point and drawing out a well defined path.<br />
<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNiALQpr1O4GpLr8NH7v7xnZHOh8vQmejdHzotk9tvJ1y17aSvTQg65OzRwTca8fxkjuN8V2SFQVSdyRPSTGpdBvhHDYkWsM4edlBXth7UPMiTvq6pMjVjnFgQFpq1NAylaYcPZ-ItuwQ/s1600/OscInitialSchro.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="301" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNiALQpr1O4GpLr8NH7v7xnZHOh8vQmejdHzotk9tvJ1y17aSvTQg65OzRwTca8fxkjuN8V2SFQVSdyRPSTGpdBvhHDYkWsM4edlBXth7UPMiTvq6pMjVjnFgQFpq1NAylaYcPZ-ItuwQ/s320/OscInitialSchro.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Example of an initial state of a neutrino at birth - pure electron like.</td></tr>
</tbody></table><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNNQnJ7uTSoj-XKMYYnm8AtrMNnlIt_rSuK5HBgShqJTC-j_1cOHHYNqv24GU2Yp34xGTP0RUVmUuxyG3_kRffvMHPb8QDjiK8-w1GUr4B6w_neW4wRe-BlQ9yU7ip-s7W5qwITP90h24/s1600/OscFinalSchro.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="301" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNNQnJ7uTSoj-XKMYYnm8AtrMNnlIt_rSuK5HBgShqJTC-j_1cOHHYNqv24GU2Yp34xGTP0RUVmUuxyG3_kRffvMHPb8QDjiK8-w1GUr4B6w_neW4wRe-BlQ9yU7ip-s7W5qwITP90h24/s320/OscFinalSchro.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Example of an final state of a neutrino at some time greater than 0</td></tr>
</tbody></table><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuhQi7CZykALiIs0p8EXa2_aAzvPl2gWQociHT_PLrORUG9yGDoiCEYwcxaiDXtL4H8b3BVnqMWJHjjIdUitEUZ_Ndoe9AD6L2Z8fM6FYuUCfjg02U9HJtyMUaPWZquvD9AXdjGjs8bb4/s1600/OscFinal.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuhQi7CZykALiIs0p8EXa2_aAzvPl2gWQociHT_PLrORUG9yGDoiCEYwcxaiDXtL4H8b3BVnqMWJHjjIdUitEUZ_Ndoe9AD6L2Z8fM6FYuUCfjg02U9HJtyMUaPWZquvD9AXdjGjs8bb4/s320/OscFinal.png" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">How probable the neutrino is to choose each flavour.</td><td class="tr-caption" style="text-align: center;"><br />
</td><td class="tr-caption" style="text-align: center;"><br />
</td><td class="tr-caption" style="text-align: center;"><br />
</td><td class="tr-caption" style="text-align: center;"><br />
</td><td class="tr-caption" style="text-align: center;"><br />
</td><td class="tr-caption" style="text-align: center;"><br />
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</td><td class="tr-caption" style="text-align: center;"><br />
</td><td class="tr-caption" style="text-align: center;"><br />
</td></tr>
</tbody></table>So from its birth at t=0 the vector that represents the neutrinos state of being is constantly changing until at some time later, say t=t1, it interacts with the world around it. When the neutrino interacts it is again asked the question of what flavour it is - the probability of which it chooses is determined by projecting the vector onto the flavour axes. The probability is the square of this projection (amplitude). As soon as the neutrino decides it becomes a pure electron, muon or tau like neutrino and behaves as such. This phenomenon is also known technically as a collapse of the wave function of the neutrino - as it changes from a haze of probability to a billiard ball.<br />
<br />
To figure out these probabilities experiments must wait patiently and look for many neutrinos. It is like measuring the probability of rolling a six on a dice by noting down the result of many rolls - but you can only roll the dice a few times a day in most cases.<br />
<br />
<br />
<u>The Passage of Time</u><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7tEYi3jmZ9RFLSh5NdmoUHujPbrg1kBNZe4wNrYtt1zM4yzb7ZDcCXy21ETT7hoxZnxflVJ7D5sGDWjS5c_QHTZQxR-W_wPB-dHA7HsRXhFtRUFVBB0HDTNLPkm9OiuSEHOwtklBioUM/s1600/SurrProb.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="248" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7tEYi3jmZ9RFLSh5NdmoUHujPbrg1kBNZe4wNrYtt1zM4yzb7ZDcCXy21ETT7hoxZnxflVJ7D5sGDWjS5c_QHTZQxR-W_wPB-dHA7HsRXhFtRUFVBB0HDTNLPkm9OiuSEHOwtklBioUM/s400/SurrProb.png" width="400" /></a></div>The speed at which the neutrinos vector traces the defined path depends on the difference in mass between the three neutrinos masses. As I have <a href="http://neutrinoscience.blogspot.com/2010/11/four-neutrinos-but-you-just-said-there.html">mentioned in a previous post this is uniquely defined by just two numbers</a>. The size of these numbers have been measured by monitoring the disappearance of electron neutrinos from the Sun (Δm<sub>12</sub>) and muon neutrinos from the atmosphere (Δm<sub>23</sub>).<br />
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The angle of initial mixture and the mass difference involved can be measured by looking at the probability of survival as a function of neutrino energy divided by the distance they have traveled. The position of the first dip in probability can tell us how quickly the neutrinos vector is spinning and therefore the Δm (in fact it is the Δm<sup>2</sup>). The size of the first dip let's us know how mixed up the neutrino was originally and therefore an angle of displacement between the mass and flavour axes.<br />
<br />
Next: The Solar Neutrino Problem and Solution <br />
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</script>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-25892384910523567882011-06-28T11:55:00.001+01:002011-10-30T12:46:02.550+00:00Coming At It From All Angles - Part 2This is a continuation of a <a href="http://bit.ly/NuBlogAng1">previous post</a>. In this post we talk a little further in depth about the mathematics behind neutrino oscillation on a road to understanding the <a href="http://bit.ly/NuBlogT2KNuE1">new exciting results released by the T2K experiment.</a><br />
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<u>Particles and Vectors</u> <br />
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So how do we describe the bizarre behaviour of neutrino in maths? It is all about rotation. My spatial awareness is not the best (I have dented cars to prove this!) but I am aware that we live three space dimensions (3D) - up-down, left-right and backwards and forwards. To chart a position in 3D space we can place a point on a graph with three axes, traditionally called x, y and z. <br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfcu6LD75KVxW_JYzkxmB7qp0i3jybFysYa00wiXShEjo6JJDcsxki3I3aqrJBviCBLNfUnWMc4prLQLCMppIony1X0QGvOxbESu8svrrqe3AoWu7FDWPOxaRhAny7hcIcAWJaLJx8cq0/s1600/Projection.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="235" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfcu6LD75KVxW_JYzkxmB7qp0i3jybFysYa00wiXShEjo6JJDcsxki3I3aqrJBviCBLNfUnWMc4prLQLCMppIony1X0QGvOxbESu8svrrqe3AoWu7FDWPOxaRhAny7hcIcAWJaLJx8cq0/s400/Projection.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Fig. 1: Projection of a vector onto an axis</td></tr>
</tbody></table>
Instead of just a point imagine an arrow now pointing from the zero point (x=0,y=0,z=0) to another point in 3D space. This arrow has a direction and size - this is a vector. You can imagine a particle, like a neutrino, as a vector in a 3D space - not just a point but an arrow with a direction (the size of the particle vector is 1 in the following).<br />
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Instead of there being just one set of 3D axes you can have multiple sets all centered at the same zero point. Each of the sets of axes describes different properties of the particle, not a position in space. One set of axes can, instead of being x,y and z spacial dimension, describe the flavour of the particles - how electron-like, muon-like and tau-like the neutrino is. Another set of axes can describe the mass of the neutrino.<br />
<br />
<u>Measuring Properties</u><br />
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<div class="separator" style="clear: both; text-align: center;">
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There is a limit on the size of the axes and therefore the size of the vector describing the particle in question - this is 1, or 100% if you like, because nothing can be more than 100% electron-like for example. Things can be less than 100% though - to find how much of each a particle is we need to project its vector onto each of the different axes.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgefkSsVXbGXYDGhcMEA7FM66tNHGcgbXGRB8S6jlIMwDV-0lGe46CwW-gK-x1qzvzA8VwoKJqG1U48I159mAddtlbpJVSII7KGfZUE0Vb4j5zUkUjFTO0iUgBj5jmHog0BtZpgo7-0ryU/s1600/InitialENuAngles.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgefkSsVXbGXYDGhcMEA7FM66tNHGcgbXGRB8S6jlIMwDV-0lGe46CwW-gK-x1qzvzA8VwoKJqG1U48I159mAddtlbpJVSII7KGfZUE0Vb4j5zUkUjFTO0iUgBj5jmHog0BtZpgo7-0ryU/s320/InitialENuAngles.png" width="278" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Fig 2: A pure electron neutrino is a mix of different masses</td></tr>
</tbody></table>
What I mean by project is really like shining a light over the vector at the axis in question and measuring the size of the shadow it casts (Fig 1). If you have a stick that is 100cm (1m) long at some angle off the floor, shine a torch from above (or either side) and you will see that the length on the floor (or the walls) is less than 1. The probability of a vector being either of the properties is then calculated as the square of the shadow length it casts. Use the corner of a room as a zero point and imagine the floor and walls as you axes and try it for yourself - this is all we are doing but in maths.<br />
<br />
<u>Mixing It All Up</u><br />
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Although intuitively we associate definite mass to electrons and the like, there is no law in nature to say that a certain flavour of particle should have a definite mass. This is displayed best by the neutrino. In our model of 3D axes outlined above this would show itself as a misalignment, a rotation between the axes. If a neutrino is born as electron-like, i.e. with its vector lying along the electron axis, then one can see automatically that it is not a definite mass but instead a mixture of all three - the neutrino vector is non-zero on all three of the mass axes (Fig 2).<br />
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<br />
<u>All Angular</u><br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpul1VD0DwhEdtqlVJjmPAxxxLBbmOHh3q2v_ed_GSdXhzvUoa90wHT1DLBZHxPddhTx6R8QokKf_1SqxeK6vgV6PLQTfv_pq_394icKoI2wecuVtz0QEXfMkAlyD-pqglXElzrtEYAM8/s1600/OscAngles.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpul1VD0DwhEdtqlVJjmPAxxxLBbmOHh3q2v_ed_GSdXhzvUoa90wHT1DLBZHxPddhTx6R8QokKf_1SqxeK6vgV6PLQTfv_pq_394icKoI2wecuVtz0QEXfMkAlyD-pqglXElzrtEYAM8/s320/OscAngles.png" width="278" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Fig 3: Three angles describe the rotation between neutrino mass and flavour. </td></tr>
</tbody></table>
The misalignment of the mass and flavour axes can be uniquely defined by three angles of rotation (Fig 3). These angles, just numbers, cannot be predicted with the maths but instead must be measured through experiments. They are measured by looking at the changing flavours of neutrino from various different sources.<br />
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There is also one other number that has to be measured - one that essentially defines the difference in overall orientation of the axes for neutrinos and their antimatter version the antineutrinos. To understand the difference between matter and antimatter is to understand the creation of the Universe from the pure energy Big Bang - more about latter in this series.<br />
<br />
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</script>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-11830227375981487052011-06-27T09:36:00.003+01:002012-04-20T02:05:25.163+01:00Coming At It From All Angles - Part 1The <a href="http://neutrinoscience.blogspot.com/2011/06/hello-there-electron-neutrino.html">T2K experiment has recently started a journey down an exciting path</a>. With more data it is hoped that T2K will eventually lead us to an clearer understanding of an essential chapter in the creation story of the Universe - but what is the experiment actually measuring? In this series of posts I will talk about the bizarre behaviour of neutrinos, what experiments need to do to characterise this behaviour and how they may hold the key to the creation story.<br />
<div>
<div>
<br /></div>
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I will cover a lot of information and link back to previous posts where I feel more information may help the reader but please do leave any questions in the comments.</div>
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<div>
<u>A Definite Possibility</u></div>
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When you go to the smallest 'quantum' scales of Nature things become strange indeed. When things interact with each other they act as definite snooker/pool balls. But, between these interactions things become hazy, waves of possibilities and probabilities. It because of this hazy probability that neutrinos are given the opportunity to change their character when they travel.</div>
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<u><br />
</u><br />
<u>All Mixed Up!</u></div>
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<br /></div>
<div>
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivBNcCmGlwajvCHauD_dpjWyQm-24P7Ily5ManNFpdtwzh3W9SY549Z3RZEufWPrEbR8DktvCKHd7s7LqaUchMJMn9oUIMl_BRVCtVMiXjcjOhXGtnL9NqOeIcY88QvWoc7zDIJdMHWGY/s1600/ConfusedNeutrino-mass.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="298" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivBNcCmGlwajvCHauD_dpjWyQm-24P7Ily5ManNFpdtwzh3W9SY549Z3RZEufWPrEbR8DktvCKHd7s7LqaUchMJMn9oUIMl_BRVCtVMiXjcjOhXGtnL9NqOeIcY88QvWoc7zDIJdMHWGY/s400/ConfusedNeutrino-mass.png" width="400" /></a>At the start of their life a neutrino knows definitely that they are electron-like, muon-like or tau-like what we call the different 'flavours' - this is because they are born in weak force interactions alongside these other particles. Ask the neutrino its mass however and it would not be certain - there is no law of Nature that states a certain flavour of particle should have a certain mass - so the neutrino is born knowing exactly what type of flavour of particle it is but not exactly what mass it has.</div>
<div>
<br /></div>
<div>
The way a particle travels is determined by their mass and energy (governed by the Schrödinger Equation). As the mixed up neutrino starts on it's journey into the big wide world, the its original confusion about its own mass changes in a well defined mathematical way. The probability that it might be either of the three possible masses continually changes.</div>
<div>
<br />
<u>When Will I See You Again?</u><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRvU1Nn7FP2MYNAPwljm5Y68Ibk5iC31X9-HPbFBVcz0reqMzHgTGREWUI1zctjOOPKO-oALGoo_fetqrbkY0jr72LpFRzXv0Arz-gqyq3QgNjdDAEIB673GP4fIo_yxmSTrOhdGGuZds/s1600/ConfusedNeutrino-flavour.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="298" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRvU1Nn7FP2MYNAPwljm5Y68Ibk5iC31X9-HPbFBVcz0reqMzHgTGREWUI1zctjOOPKO-oALGoo_fetqrbkY0jr72LpFRzXv0Arz-gqyq3QgNjdDAEIB673GP4fIo_yxmSTrOhdGGuZds/s400/ConfusedNeutrino-flavour.png" width="400" /></a></div>
On the extremely rare occasion a neutrino decides to interact again with the outside world it must do so, as in its birth, via the weak force. Here it is faced with a choice of yet again being electron-like, muon-like or tau-like. How probable it is to choose either of these flavours depends on the mixture of its possible masses. Because the mixture of masses has changed during its lifetime there are now non-zero probabilities that the neutrino wants to be a different flavour to which it was born - it is now uncertain of what flavour it is!</div>
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But choose it must, as this is the only way in which a neutrino may interact and its presence be seen. This change of mind as to which weak flavour they are, electron, muon or tau is called neutrino oscillation.<br />
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<a href="http://neutrinoscience.blogspot.com/2011/06/coming-at-it-from-all-angles-part-2.html">Part 2: The maths and numbers behind neutrino oscillation</a> </div>
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</script>Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-36788610612974835012011-06-15T11:09:00.006+01:002011-06-27T17:23:26.834+01:00Hello There Electron Neutrino<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="http://www.kek.jp/intra-e/press/2011/images/J-PARC_T2Kneutrino5.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="245" src="http://www.kek.jp/intra-e/press/2011/images/J-PARC_T2Kneutrino5.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A candidate electron like neutrino event in Super-K</td></tr>
</tbody></table>After weeks of rumours, and reporters even contacting yours truly for the scoop, the latest results are finally in - The results released by the Tokai to Kamioka (T2K) experiment that is! Today T2K released results in seminars, a <a href="http://www.kek.jp/intra-e/press/2011/J-PARC_T2Kneutrino.html">press release</a> and the first <a href="http://arxiv.org/abs/1106.2822">physics paper</a> to be released by the experiment - results that sent waves of excitement through the particle physics and larger community. But why?<br />
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<u>The Results</u><br />
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Before the earthquake of March 11th the T2K created about 2% of the neutrinos it hopes to in the lifetime in the experiment and fired them in a beam at its particle detectors. A group of detectors just 280m from the creation point of the neutrinos tells us how many neutrinos of <a href="http://neutrinoscience.blogspot.com/2010/11/particles.html">each type</a> (<a href="http://neutrinoscience.blogspot.com/2010/11/electrons-and-muons.html">muon or electron</a> type) we are firing. The neutrinos then continue 295km to the <a href="http://neutrinoscience.blogspot.com/2010/10/super-k-in-super-k-sonic-booooum.html">Super Kamiokande</a> (Super-K) detector where again the number of each type <a href="http://neutrinoscience.blogspot.com/2011/05/hunting-neutrinos-at-super-kamiokande.html">is determined</a>.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoOGzhhT_Cz_syunOEINfKr0yXyCXRGt_V-uJhCz5KjIYwq8NJcuFG6aqsDwratpG62XY9dtvfnRhac8POJJ81VJ4JBFa6ucMjajXLVnJ-DZABHywqChCsxdzm4QY78J_txFcpS6YVE9Y/s1600/RecoEnergy.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="296" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoOGzhhT_Cz_syunOEINfKr0yXyCXRGt_V-uJhCz5KjIYwq8NJcuFG6aqsDwratpG62XY9dtvfnRhac8POJJ81VJ4JBFa6ucMjajXLVnJ-DZABHywqChCsxdzm4QY78J_txFcpS6YVE9Y/s320/RecoEnergy.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The final cut, on neutrino energy,to select electron like <br />
neutrino events.</td></tr>
</tbody></table><a href="http://neutrinoscience.blogspot.com/2011/01/birth-death-and-neutrino-beams.html">T2K creates almost 100% Muon type neutrinos</a> and hopes that because of the <a href="http://neutrinoscience.blogspot.com/2010/11/identity-crisis-in-japan.html">identity crisis</a> neutrinos undergo some of these might decide to turn into electron neutrinos. With the small amount of data taken, 88 neutrinos were clearly seen in Super-K. After a number of cuts on various aspects of the data, 6 of these were <a href="http://neutrinoscience.blogspot.com/2011/05/hunting-neutrinos-at-super-kamiokande.html">determined</a> to be be electron like. As I mentioned the beam of neutrinos fired is ALMOST 100% muon neutrinos so there is a small contamination of electron neutrinos. This, plus other particles that can mimic electron neutrinos, means that we were already expecting to see 1.5 background electron like events.<br />
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With 6 events seen and 1.5 expected we can say with 99.3% confidence that we have seen some of the muon neutrinos change into electron neutrinos. This is a strong hint and the first of its kind.<br />
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<u>The Physics</u><br />
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The <a href="http://neutrinoscience.blogspot.com/2010/11/identity-crisis-in-japan.html">changing personality</a> of the neutrino is a natural result of quantum mechanics. Neutrinos, as other <a href="http://neutrinoscience.blogspot.com/2010/11/particles.html">fundamental particles</a> are both a wave (when travelling) and a particle (when interacting). The wave like nature allows the probability that the neutrino is muon-like or electron-like to change as it travels from creation to detection. As it is a purely quantum mechanical effect we have well understood mathematics which describes the evolution of these probabilities.<br />
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If we are to understand the character of the neutrino there are six numbers that we have to measure from Nature to plug into the maths.<br />
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Two of these numbers determine how fast the neutrino can change its character. These are the<a href="http://neutrinoscience.blogspot.com/2010/11/four-neutrinos-but-you-just-said-there.html"> difference in the mass</a> of the three neutrino masses. These numbers determine where you place your detectors to see the character differences.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyi1n-ote_aipdCImaYDnGFbdw5GiNasuZuw8Z3kNLgBRspPjSkyessVhacql3Jr2f0UqdxegaLU1hhSbIfVYvGTTHNMKo2jJRjiNpbuPJ9tV_qQ-JN7DTP59Hxn8JzAe0NmbXjYoGRPc/s1600/PMNS.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="90" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyi1n-ote_aipdCImaYDnGFbdw5GiNasuZuw8Z3kNLgBRspPjSkyessVhacql3Jr2f0UqdxegaLU1hhSbIfVYvGTTHNMKo2jJRjiNpbuPJ9tV_qQ-JN7DTP59Hxn8JzAe0NmbXjYoGRPc/s400/PMNS.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">How mixed up is the neutrino at birth? <br />
Some of the maths involved - just to scare you! </td></tr>
</tbody></table>Three of these numbers determine how mixed up the neutrino is to start with (diagram above). Two of these numbers have been measured (red,blue), but still need to be accurately measured. The third and final number seems to be really small, so much so that it has until now been taken to be zero. It is this third number, which we call θ-13, that determines how many muon neutrinos decide to become electron neutrinos in the T2K experiment. So the fact that T2K sees electron neutrinos appearing from muon neutrinos gives a strong hint that this number is in fact greater than zero.<br />
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Finally there is one number which tells us how <a href="http://neutrinoscience.blogspot.com/2010/11/symmetries-and-birth-of-universe.html">neutrinos (matter) and anti-neutrinos (anti-matter) differ</a> in their character crisis. This final number is always found multiplied by the small number described above - so to measure the difference between matter and anti-matter this we need the small number to be greater than zero (anything x 0 = 0) and we then need to know this number. T2K hopes to not only measure the small number but also use anti-neutrinos to start to look for the difference between matter and anti-matter.<br />
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With just 2% of data the experiment hopes to take in its lifetime, T2K has shown that it has started a path down an exciting route. Efforts are now underway to get T2K up and running once more after the earthquake, so that we may continue this journey toward understanding the difference between matter and anti-matter and the creation of our Universe.<br />
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P.s. As a follow up I am writing a series of posts describing how we quantify the bizarre nature of the neutrino - <a href="http://neutrinoscience.blogspot.com/2011/06/coming-at-it-from-all-angles-part-1.html">check it out here</a>.Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0tag:blogger.com,1999:blog-6334446934922301536.post-9448615755496491222011-06-08T11:04:00.003+01:002011-06-15T14:27:11.513+01:00First T2K Paper<span class="Apple-style-span" style="color: #333333; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: 14px;"><b>*** You can find the latest results </b></span><span class="Apple-style-span" style="color: #333333; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: 14px;"><a href="http://neutrinoscience.blogspot.com/2011/06/hello-there-electron-neutrino.html" style="color: #225588; text-decoration: none;"><b>here</b></a></span><span class="Apple-style-span" style="color: #333333; font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif; font-size: 14px;"><b> ***</b></span><br />
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Today the Tokai to Kamioka (T2K) experiment released its <a href="http://arxiv.org/abs/1106.1238">first collaboration paper</a>. A technical paper, it describes the setup of the experiment and covers the entire infrastructure - how the experiment gets from neutrinos to data. The paper was immediately accepted for publication in the journal Nuclear Instruments and Methods A (NIM-A) and will be in next months edition of the journal.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgq666LAi4qNNxiVozOnPm6-EK9NxopIVOSoJHbIR_8ETQeOpCBsKbXbcb-_2upfG_Zf0Q4HW0xFtBcqfr6yUkNyqMy9lCru91pkIhyYdZUDV3WiIwntmGbsz3jVcJg2t4yUB3XSKhYekY/s1600/t2knimMe2.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgq666LAi4qNNxiVozOnPm6-EK9NxopIVOSoJHbIR_8ETQeOpCBsKbXbcb-_2upfG_Zf0Q4HW0xFtBcqfr6yUkNyqMy9lCru91pkIhyYdZUDV3WiIwntmGbsz3jVcJg2t4yUB3XSKhYekY/s400/t2knimMe2.png" width="282" /></a></div>All particle physics experiments begin their collaborative publications with a NIM paper before physics results are released. The description of experimental procedure in such papers are important to reference to make sense of any future physics results that are published. This is a massive milestone for T2K, which is the largest collaboration/experiment of its type with around 500 scientists and engineers working on the Japanese led experiment - see front page on which I have shamelessly highlighted my name :-) .<br />
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With the release of the NIM paper exciting times lie ahead for the T2K experiment as we anticipate physics publications. Watch this space.<br />
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You can get the paper from the pre-print arXiv <a href="http://arxiv.org/abs/1106.1238">here</a>.<br />
Please browse my blog for more info on the T2K experiment [<a href="http://bit.ly/NuBlogOsc">1</a> <a href="http://bit.ly/NuBlogNuBul">2</a>] , the detectors [<a href="http://bit.ly/NuBlogSK">3</a> <a href="http://bit.ly/h7ZeQk">4</a>] used and physics behind the experiment [ <a href="http://bit.ly/NuBlogParticles">5</a> <a href="http://bit.ly/NuBlogOsc">2</a> <a href="http://bit.ly/NuBlogSymm">6</a> ]. Or leave me questions in the comments section and I will reply with a comment or a blog post if I have far too much to talk about.Benhttp://www.blogger.com/profile/13783930658796669281noreply@blogger.com0