<div dir="ltr"><div><div><div><div>Dear Chandra,<br><br></div>I did not read the paper or analyze the announcement in detail, as you did, so your model might still hold for this work.<br><br></div>It did focus your attention so that i could ask you a question "What is your view on identical particles?"<br><ol><li>If 2 identical particles, each described by a wave function, collide head on, do they reflect from each other, go thru each other, neither, or both? <br></li><li>Would you explain your answer?<br></li><li>Or, is the question bad, is there insufficient information, or is the result just indeterminate? <br></li></ol></div>How I phrase the next question depends on how you answer the above.<br><br></div>Andrew<br>_____________________________<br><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Aug 28, 2017 at 12:12 PM, Roychoudhuri, Chandra <span dir="ltr"><<a href="mailto:chandra.roychoudhuri@uconn.edu" target="_blank">chandra.roychoudhuri@uconn.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal" style="text-autospace:none">Hello Everybody: <u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">I have again looked at the original ATLAS publication. The experiment is a very high energy non-linear phenomenon in the vicinity of highly charged Pb-atoms. As an experimental physicist in the field of optical
sciences, I do not find the experiment as generalizable to state “light-by-light scattering” phenomenon. The scattering of high energy Gamma-Gamma wave packets, still in the vicinity of highly-charged, high energy Pb-nuclei, should not be generalized to incorporate
the entire band of EM radiation, from radio, to micro, to visible, to X-ray wave packets. [See below the reference to the original paper.]<u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none"><u></u> <u></u></p>
<p class="MsoNormal" style="text-autospace:none">I do find it sad that the title of the paper uses generalized expression “Evidence for light-by-light scattering…”; instead of calling out that it is a very high energy complex phenomenon. It is susceptible to
subjective interpretations of the theory since the interaction of the parameters are quite complex, which are not yet all quantified very well.
<u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">In the process, we are pro-actively weakening the platform of “Evidence based science”, which has very serious long-term re-percussions for the entire scientific enterprise.<u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none"><u></u> <u></u></p>
<p class="MsoNormal" style="text-autospace:none">Of course, the technical content of the paper is scientifically beyond criticism. But, in the age, when the most powerful country is trying to run the world by “twit-headlines”; we need to be a lot more thoughtful!
<u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none"><u></u> <u></u></p>
<p class="MsoNormal" style="text-autospace:none">Chandra.<u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:Whitney-Semibold;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:Whitney-Semibold"><a href="https://www.nature.com/nphys/journal/vaop/ncurrent/pdf/nphys4208.pdf" target="_blank">https://www.nature.com/nphys/<wbr>journal/vaop/ncurrent/pdf/<wbr>nphys4208.pdf</a><u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:24.0pt;font-family:Whitney-Semibold"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:24.0pt;font-family:Whitney-Semibold">Evidence for light-by-light scattering in heavy-ion<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:24.0pt;font-family:Whitney-Semibold">collisions with the ATLAS detector at the LHC<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:Whitney-Semibold">ATLAS Collaboration</span><span style="font-size:9.0pt;font-family:Whitney-Semibold">†<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">Light-by-light scattering (</span></b><span style="font-size:9.5pt;font-family:RMTMIH">
</span><span style="font-size:9.5pt;font-family:MTSYH">!</span><span style="font-size:9.5pt;font-family:RMTMIH">
</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">) is a quantum-mechanical process that is forbidden in the classical theory of<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">generated by ultra-relativistic colliding lead ions. Using 480
</span></b><span style="font-size:9.5pt;font-family:txbmia">_</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">b</span></b><span style="font-size:5.5pt;font-family:"Arial",sans-serif"></span><b><span style="font-size:5.5pt;font-family:Whitney-Bold">1
</span></b><b><span style="font-size:9.5pt;font-family:Whitney-Bold">of lead–lead collision data recorded at a centre-of-mass<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">candidate events were observed with an expected background of 2.6
</span></b><span style="font-size:9.5pt;font-family:MTSYH">_ </span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">0.7 events. After background subtraction and analysis<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">corrections, the fiducial cross-section of the process Pb</span></b><span style="font-size:9.5pt;font-family:MTSYH">C</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">Pb
(</span></b><span style="font-size:9.5pt;font-family:RMTMIH"> </span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">)</span></b><span style="font-size:9.5pt;font-family:MTSYH">!</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">Pb</span></b><span style="font-size:5.5pt;font-family:RMTMIH">.</span><span style="font-size:5.5pt;font-family:MTSYH">_</span><span style="font-size:5.5pt;font-family:RMTMIH">/</span><span style="font-size:9.5pt;font-family:MTSYH">C</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">Pb</span></b><b><span style="font-size:5.5pt;font-family:Whitney-Bold">(</span></b><span style="font-size:5.5pt;font-family:MTSYH">_</span><b><span style="font-size:5.5pt;font-family:Whitney-Bold">)</span></b><span style="font-size:9.5pt;font-family:RMTMIH">
</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">, for photon transverse energy
</span></b><b><i><span style="font-size:9.5pt;font-family:Whitney-BoldItalic">E</span></i></b><b><span style="font-size:5.5pt;font-family:Whitney-Bold">T</span></b><span style="font-size:9.5pt;font-family:RMTMIH">></span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">3
GeV,<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">photon absolute pseudorapidity
</span></b><span style="font-size:9.5pt;font-family:MTSYH">j</span><span style="font-size:9.5pt;font-family:RMTMIH">_</span><span style="font-size:9.5pt;font-family:MTSYH">j</span><span style="font-size:9.5pt;font-family:RMTMIH"><</span><b><span style="font-size:9.5pt;font-family:Whitney-Bold">2.4,
diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span style="font-size:9.5pt;font-family:Whitney-Bold">than 2 GeV and diphoton acoplanarity below</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u><u></u></span></p><span class="">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> General [mailto:<a href="mailto:general-bounces%2Bchandra.roychoudhuri" target="_blank">general-bounces+<wbr>chandra.roychoudhuri</a>=<a href="mailto:uconn.edu@lists.natureoflightandparticles.org" target="_blank">uconn.<wbr>edu@lists.<wbr>natureoflightandparticles.org</a>]
<b>On Behalf Of </b>Andrew Meulenberg<br>
<b>Sent:</b> Sunday, August 27, 2017 10:39 AM<br>
<b>To:</b> Nature of Light and Particles - General Discussion <<a href="mailto:general@lists.natureoflightandparticles.org" target="_blank">general@lists.<wbr>natureoflightandparticles.org</a>><wbr>; Andrew Meulenberg <<a href="mailto:mules333@gmail.com" target="_blank">mules333@gmail.com</a>><br>
<b>Cc:</b> robert hudgins <<a href="mailto:hudginswr@msn.com" target="_blank">hudginswr@msn.com</a>><br>
<b>Subject:</b> [General] light light interactions<u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">For those who argue against light-light interactions<u></u><u></u></p>
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<p class="MsoNormal"><br>
<a href="http://physicsworld.com/cws/article/news/2017/aug/18/light-is-seen-to-scatter-off-light" target="_blank">http://physicsworld.com/cws/<wbr>article/news/2017/aug/18/<wbr>light-is-seen-to-scatter-off-<wbr>light</a><u></u><u></u></p>
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