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<div dir="ltr">Dear All</div>
<div dir="ltr">Yet you cannot throw it out without discussing all</div>
<div dir="ltr">these very valid points. <span id="ms-outlook-ios-cursor"></span></div>
<div dir="ltr">Simonetta </div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Psqateic <psqateic-bounces@jlab.org> on behalf of Xiangdong Ji <xji@umd.edu><br>
<b>Sent:</b> Monday, August 22, 2022 3:10:28 PM<br>
<b>To:</b> Keh-Fei Liu <liu@g.uky.edu><br>
<b>Cc:</b> psqateic@jlab.org <psqateic@jlab.org><br>
<b>Subject:</b> Re: [Psqateic] [EXTERNAL] Re: PSQ@EIC White Paper</font>
<div> </div>
</div>
<div>
<div dir="ltr">hi, All,
<div> C-bar is a twist-4 form factor, hard to measure in high-energy scattering where</div>
<div>one probes quarks and gluons directly. Moreover, it depends on how does one</div>
<div>define teh separation of trace parts of the quarks and gluons. In the simplest scenario, </div>
<div>they are related to the form factors of the scalars, F^2 and \psi-bar\psi. </div>
<div> C-bar generates a part of the momentum-current density of the quarks and gluons separately. </div>
<div>but cancels in the sum. In the present writing, no separation</div>
<div>of the momentum-current density is made because such separation has additional </div>
<div>scheme dependence due to different ways of deriving the trace anomaly. </div>
<div> </div>
<div>Xiangdong </div>
<div><br>
</div>
<div><br>
</div>
</div>
<br>
<div class="x_gmail_quote">
<div dir="ltr" class="x_gmail_attr">On Wed, Aug 17, 2022 at 4:00 PM Keh-Fei Liu <<a href="mailto:liu@g.uky.edu">liu@g.uky.edu</a>> wrote:<br>
</div>
<blockquote class="x_gmail_quote" style="margin:0px 0px 0px 0.8ex; border-left:1px solid rgb(204,204,204); padding-left:1ex">
<div>Dear Volker:<br>
<br>
In a simple scheme, the forward matrix elements are \bar{C}_q = 1/4 (quark condensate - <x>_q (\mu) M)<br>
and \bar{C}_g = 1/4 (trace anomaly - <x>_g (\mu) M). The \pi N sigma term can be obtained from \pi N scattering, the strangeness<br>
sigma term can be obtained from the lattice. The momentum fractions can be obtained from global fitting of DIS. How to obtain<br>
the trace anomaly experimentally is a challenge. All of them can be and have been obtained in lattice calculations. The current<br>
challenge for lattice is to calculate their form factors including the quark and glue parts of B (t) and C(t). In other words, all the<br>
gravitational FFs including \bar{C}.<br>
<br>
Best,<br>
Keh-Fei<br>
<br>
<br>
<br>
<br>
<br>
<div>On 8/17/22 6:59 AM, Volker Burkert wrote:<br>
</div>
<blockquote type="cite">
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
Dear Keh-Fei and Oleg, </div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
I like the idea to acknowledge the existence of additional terms that cancel when summing quarks and gluons, but don't discuss them in any detail. </div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
<span style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">I have not seen a description of how \bar{C} can be measured in experiment, either for quarks or for gluons, separately. If there are such proposals we could refer
to them in the WP. </span><br>
</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
Perhaps we could mention that \bar{C} may be computed in LQCD and then used as correction to the EMT for quarks and gluons separately? </div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
Volker</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
<br>
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<div id="x_gmail-m_-1557232720038714160divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> teryaev
<a href="mailto:teryaev@jinr.ru" target="_blank"><teryaev@jinr.ru></a><br>
<b>Sent:</b> Wednesday, August 17, 2022 4:16 AM<br>
<b>To:</b> Keh-Fei Liu <a href="mailto:liu@g.uky.edu" target="_blank"><liu@g.uky.edu></a><br>
<b>Cc:</b> Volker Burkert <a href="mailto:burkert@jlab.org" target="_blank"><burkert@jlab.org></a>;
<a href="mailto:psqateic@jlab.org" target="_blank">psqateic@jlab.org</a> <a href="mailto:psqateic@jlab.org" target="_blank">
<psqateic@jlab.org></a><br>
<b>Subject:</b> Re: [Psqateic] [EXTERNAL] Re: PSQ@EIC White Paper</font>
<div> </div>
</div>
<div><font size="2"><span style="font-size:11pt">
<div>Dear Keh-Fei,<br>
<br>
<br>
You are completely right, there are terms cancelling when the when quark <br>
and gluon contributions are summed (due to equivalence principle, whose <br>
extension may be used to explain their smallness even separately), <br>
including C\bar ("proton cosmological constant") together with<br>
anomalous gravitomagnetic moment, and often forgotten gravitoelectric <br>
dipole moment. violating also CP. Indeed, C \bar is crucially important <br>
when (separate) traces are calculated.<br>
<br>
Maybe in the text one can add after (6) something like "There are also <br>
terms cancelling<br>
in the sum of quark and gluons due to conservation laws and equivalence <br>
principle"?<br>
<br>
best regards,<br>
Oleg<br>
<br>
Keh-Fei Liu §á§Ú§ã§Ñ§Ý(§Ñ) 2022-08-13 08:56:<br>
> Dear Volker:<br>
> <br>
> Now that we agree that there are \bar{C} terms in Eq. (6), take<br>
> the trace of the GFF in the rest frame, one<br>
> has the expression <T_{\mu\mu}> = [(A_q(0) + A_g(0)]M + Tr-Anomaly +<br>
> chiral condensate - [(A_q(0) + A_g(0)]M = Tr-Anomaly<br>
> +chiral condensate which is the correct expression. The last three<br>
> terms come from \bar{C} which is zero (for a good reason because<br>
> it is the stability condition). If one drops them first, one ends up<br>
> with the expression of [(A_q(0) + A_g(0)]M. Please explain why<br>
> it is acceptable and not wrong with an expression where the trace of<br>
> EMT does not contain trace anomaly. \bar{C} exists in many<br>
> publications in the literature, I don't understand the rationale for<br>
> dropping it in this document. It leads to (unintended) consequences.<br>
> <br>
> Best,<br>
> Keh-Fei<br>
> <br>
> On 8/12/22 4:07 PM, Volker Burkert wrote:<br>
> <br>
>> Dear Keh-Fei,<br>
>> <br>
>> * There is agreement for eq.(6) which deals with quark and gluon<br>
>> EMT separately, and the \bar{C} is needed (with opposite sign for q<br>
>> and g).<br>
>> * For eq.(19), which deals with the full EMT (quark + gluons} the<br>
>> \bar{C} terms should cancel out to zero, and the term \bar{C} should<br>
>> not appear.<br>
>> <br>
>> *<br>
>> <br>
>> *<br>
>> * Volker<br>
>> <br>
>> *<br>
>> <br>
>> -------------------------<br>
>> <br>
>> From: Keh-Fei Liu <a href="mailto:liu@g.uky.edu" target="_blank"><liu@g.uky.edu></a><br>
>> Sent: Friday, August 5, 2022 8:35 AM<br>
>> To: Volker Burkert <a href="mailto:burkert@jlab.org" target="_blank"><burkert@jlab.org></a>;
<a href="mailto:psqateic-request@jlab.org" target="_blank">psqateic-request@jlab.org</a><br>
>> <a href="mailto:psqateic-request@jlab.org" target="_blank"><psqateic-request@jlab.org></a><br>
>> Cc: Lorc¨¦ C¨¦dric (M.) <a href="mailto:cedric.lorce@polytechnique.edu" target="_blank">
<cedric.lorce@polytechnique.edu></a><br>
>> Subject: [EXTERNAL] Re: [Psqateic] PSQ@EIC White Paper<br>
>> <br>
>> Dear Volker and Latifa:<br>
>> <br>
>> Thank you for your tremendous effort in organizing this<br>
>> valuable whitepaper for the community.<br>
>> <br>
>> I now have a firm argument to show that one cannot drop<br>
>> the \bar{C} term in Eqs. (6) and (19). Take the<br>
>> forward FF of the trace T_{\mu\mu}, they give (A_q(0) + A_g(0))M.<br>
>> This is a trivial and meaningless result. It relates<br>
>> the matrix element of the trace to the mass via a sum rule of<br>
>> traceless matrix elements. It does not have the anomaly.<br>
>> Only when the \bar{C} is retained, do you get the correct expression<br>
>> with the anomaly. We should put the \bar{C} term back<br>
>> in these equations.<br>
>> <br>
>> Best,<br>
>> Keh-Fei<br>
>> <br>
>> On 8/3/22 4:33 PM, Volker Burkert wrote:<br>
>> <br>
>>> Dear Colleagues,<br>
>>> <br>
>>> We are sending you this email because you have registered to<br>
>>> participate in at least one of the workshops presented below,<br>
>>> which were held on December 15-16, 2020, March 17-19, 2021, and<br>
>>> July 19-23, 2021.<br>
>>> <br>
>>> One of the main goals of these workshops was to develop a white<br>
>>> paper focused on high-impact science requiring high integrated<br>
>>> luminosity at the low-to-medium center-of-mass energy of the U.S.<br>
>>> Electron-Ion Collider project.<br>
>>> <br>
>>> This white paper is ready to be submitted for publication. As a<br>
>>> participant in the workshop series, we invite you to become a<br>
>>> co-author of this white paper, which can be found at this link:<br>
>>> <br>
>> <br>
> <a href="https://www.femtocenter.org/sites/default/files/docs/PSQ_EIC_White_Paper.pdf" target="_blank">
https://www.femtocenter.org/sites/default/files/docs/PSQ_EIC_White_Paper.pdf</a><br>
>>> [1]<br>
>>> <br>
>>> Please visit this link and review the scope and content of the<br>
>>> white paper. If you decide to co-author the WP, please send an<br>
>>> email to <a href="mailto:burkert@jlab.org" target="_blank">burkert@jlab.org</a> no later than August 12. You may also<br>
>>> suggest minor changes to the text, acknowledgements, and<br>
>>> references, or make comments that would improve the WP.<br>
>>> <br>
>>> We have an agreement with a journal to publish the paper and we<br>
>>> need to submit the final version by August 20.<br>
>>> <br>
>>> With best regards,<br>
>>> <br>
>>> Volker & Latifa<br>
>>> <br>
>>> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_9794&d=DwIDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=Qy-CQv_msBooo8cd6Jy97FsQwD8soQkuCbKcwOzXyRURXIXufQPQRH2VFLMnTGww&s=S77fnwvL0qr9S0UjhFrOn1UKkpBtmyd0ngSd30jkvnM&e=" target="_blank">
https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_9794&d=DwIDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=Qy-CQv_msBooo8cd6Jy97FsQwD8soQkuCbKcwOzXyRURXIXufQPQRH2VFLMnTGww&s=S77fnwvL0qr9S0UjhFrOn1UKkpBtmyd0ngSd30jkvnM&e=</a>
[2]<br>
>>> <br>
>>> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_10677&d=DwIDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=Qy-CQv_msBooo8cd6Jy97FsQwD8soQkuCbKcwOzXyRURXIXufQPQRH2VFLMnTGww&s=fKbED_GbnFDO9bFXhGMzRrvCfcXJWfnRR1S8j0R6yhM&e=" target="_blank">
https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_10677&d=DwIDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=Qy-CQv_msBooo8cd6Jy97FsQwD8soQkuCbKcwOzXyRURXIXufQPQRH2VFLMnTGww&s=fKbED_GbnFDO9bFXhGMzRrvCfcXJWfnRR1S8j0R6yhM&e=</a>
[3]<br>
>>> <br>
>>> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_11669&d=DwIDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=Qy-CQv_msBooo8cd6Jy97FsQwD8soQkuCbKcwOzXyRURXIXufQPQRH2VFLMnTGww&s=Qcy4YcgzWFq0QuKBEPSZwhN7LZBCAp-YbjHSGZmhWH8&e=" target="_blank">
https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_11669&d=DwIDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=Qy-CQv_msBooo8cd6Jy97FsQwD8soQkuCbKcwOzXyRURXIXufQPQRH2VFLMnTGww&s=Qcy4YcgzWFq0QuKBEPSZwhN7LZBCAp-YbjHSGZmhWH8&e=</a>
[4]<br>
>>> <br>
>>> _______________________________________________<br>
>>> Psqateic mailing list<br>
>>> <a href="mailto:Psqateic@jlab.org" target="_blank">Psqateic@jlab.org</a><br>
>>> <a href="https://mailman.jlab.org/mailman/listinfo/psqateic" target="_blank">
https://mailman.jlab.org/mailman/listinfo/psqateic</a><br>
> <br>
> <br>
> <br>
> Links:<br>
> ------<br>
> [1] <br>
> <a href="https://www.femtocenter.org/sites/default/files/docs/PSQ_EIC_White_Paper.pdf" target="_blank">
https://www.femtocenter.org/sites/default/files/docs/PSQ_EIC_White_Paper.pdf</a><br>
> [2] <br>
> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_9794&d=DwMDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=5AYW9vwxxp8DN9axYcgThaO2tDVhNhrtj-XHvMm22kfS_MbCzGceMTTjt26SJakY&s=4daDQQx1-C0DPsG0iFTkbWjsPATQb5ZddY_N9OGquj0&e=" target="_blank">
https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_9794&d=DwMDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=5AYW9vwxxp8DN9axYcgThaO2tDVhNhrtj-XHvMm22kfS_MbCzGceMTTjt26SJakY&s=4daDQQx1-C0DPsG0iFTkbWjsPATQb5ZddY_N9OGquj0&e=</a><br>
> [3] <br>
> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_10677&d=DwMDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=5AYW9vwxxp8DN9axYcgThaO2tDVhNhrtj-XHvMm22kfS_MbCzGceMTTjt26SJakY&s=vIOR4EUCQxbO8iay3K1a8zheeXLc26lrKytTPA4AF_U&e=" target="_blank">
https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_10677&d=DwMDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=5AYW9vwxxp8DN9axYcgThaO2tDVhNhrtj-XHvMm22kfS_MbCzGceMTTjt26SJakY&s=vIOR4EUCQxbO8iay3K1a8zheeXLc26lrKytTPA4AF_U&e=</a><br>
> [4] <br>
> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_11669&d=DwMDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=5AYW9vwxxp8DN9axYcgThaO2tDVhNhrtj-XHvMm22kfS_MbCzGceMTTjt26SJakY&s=ULJyvLIlwTDZWjvQsqoes6fwCcIVQE67gO8XWJup3aI&e=" target="_blank">
https://urldefense.proofpoint.com/v2/url?u=https-3A__indico.bnl.gov_event_11669&d=DwMDaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=vVqGQabj76hiyFv-SdFNhS9JnbDxELkn2szNoXMYQyo&m=5AYW9vwxxp8DN9axYcgThaO2tDVhNhrtj-XHvMm22kfS_MbCzGceMTTjt26SJakY&s=ULJyvLIlwTDZWjvQsqoes6fwCcIVQE67gO8XWJup3aI&e=</a><br>
> _______________________________________________<br>
> Psqateic mailing list<br>
> <a href="mailto:Psqateic@jlab.org" target="_blank">Psqateic@jlab.org</a><br>
> <a href="https://mailman.jlab.org/mailman/listinfo/psqateic" target="_blank">https://mailman.jlab.org/mailman/listinfo/psqateic</a><br>
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