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Hi Richard,</div>
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You have nice slides and I have only one basic comment:</div>
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<div><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">Slide, bullet #3 says: "The proton mass radius is significantly different from the charge radius (0.84fm), suggesting that ist 'gluon radius' is significantly
smaller than its 'quark radius' [4]". (see also conclusions)</span></div>
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<div><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">a) there is no such things as a "gluon radius" or a "quark radius". The size of an object can only be </span><font face="Calibri, Arial, Helvetica, sans-serif">measured
with a certain probe. Electromagnetic probe measures the "charge radius", J/Psi probe can measure the "gluon mass radius" because it has spin=1, and it "conspires" with the incoming photon that also has spin=1 to form a system of spin=2. That is the same
as the "graviton", which has spin=2. That is why it couples to "mass" as it looks like gravity interaction. Its a bit more complicated, but that's the basic concept. </font></div>
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<div>b) In order to measure the "quark mass radius" , one has to use an appropriate probe, e.g. DVCS, where one has 2 photons with spin 1 each coupling again to spin=2 ....... <br>
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<div><font face="Calibri, Arial, Helvetica, sans-serif"><span><span>c) similar comment for conlusion slide. </span><br>
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<font face="Calibri, Arial, Helvetica, sans-serif"><span><span>Best,</span></span></font></div>
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<font face="Calibri, Arial, Helvetica, sans-serif"><span><span>Volker</span></span></font></div>
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<p><span style="font-size:20pt;font-family:CenturyGothic;color:rgb(255, 255, 255)" class="ContentPasted0"> proton mass radius is significantly different from the charge radius (</span><span style="font-size:20pt;font-family:CambriaMath;color:rgb(255, 255, 255)" class="ContentPasted0">𝑅</span><span style="font-size:15pt;font-family:CambriaMath;color:rgb(255, 255, 255);vertical-align:-4pt" class="ContentPasted0">𝑐<span class="Apple-converted-space ContentPasted0"> </span></span><span style="font-size:20pt;font-family:CambriaMath;color:rgb(255, 255, 255)" class="ContentPasted0">=
0.8409 ± 4 ∙ 10</span><span style="font-size:15pt;font-family:CambriaMath;color:rgb(255, 255, 255);vertical-align:7pt" class="ContentPasted0">−4<span class="Apple-converted-space ContentPasted0"> </span></span><span style="font-size:20pt;font-family:CenturyGothic;color:rgb(255, 255, 255)" class="ContentPasted0">fm),
suggesting that its gluon radius is significantly smaller than its quark radius [4].</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Clas_hadron <clas_hadron-bounces@jlab.org> on behalf of Richard Tyson (PGR) via Clas_hadron <clas_hadron@jlab.org><br>
<b>Sent:</b> Thursday, October 20, 2022 1:53 PM<br>
<b>To:</b> CLAS Hadron <clas_hadron@jlab.org><br>
<b>Subject:</b> [Clas_hadron] [EXTERNAL] Slides for EUNPC</font>
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Hi All,</div>
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I'm going to give a talk at the <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.cern.ch_event_1104299_&d=DwMFCQ&c=CJqEzB1piLOyyvZjb8YUQw&r=33hEheRcHuqzMP4K5hhMDPge6hQHiwXozGe7lR_eSfg&m=Xz6NFSC0nPCXJgDlknojl9AFKEY3vRTvtTRXRfBBasDZebXkxPWDIAkDuBZZd2r6&s=JVwTWKMQ4syAYDMkIbyYjjzuUSN3lcrEy59P-hfdkow&e=" data-auth="NotApplicable" title="https://indico.cern.ch/event/1104299/" data-safelink="true" data-linkindex="0" class="x_ContentPasted0">
EUNPC</a> Conference next week on J/ψ Near-Threshold Photoproduction off the Proton and Neutron with CLAS12 and wanted to check that this if fine with you all, sorry for the short notice. I've attached my
<span data-markjs="true"><span data-markjs="true" class="x_ContentPasted0">slides</span></span>; any feedback is welcome!<br class="x_ContentPasted0">
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Thanks,<br class="x_ContentPasted0">
Richard</div>
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