List for the 2014 Hot QCD White Paper Writing Group

["W.A. Zajc" <zajc AT nevis.columbia.edu>]

Hello all (again):

In a message to Krishna a day or too ago I made a successful theoretical prediction - that when the White Paper was posted we would receive “please reference me too” messages. Below is the first of what I hope is not many.

All of the remarks below are concentrated on the Quarkonia section. Tony and Ralf - can you address these? If you prefer for me to upload any edits (that you would suggest) and new references to github, that is OK - I’ve had a lot of practice recently.

I am sending this to the list rather than just to Tony and Ralf because there is a general issue of how we handle such requests. Your thoughts on this would be appreciated. For starters, I don’t intend this to be a ‘living document’. At some point in the near-future we will stop updating it. We would obviously want to fix mistakes and misstatements. 

Best regards,

Bill

—————————————

W.A. Zajc

I.I. Rabi Professor of Physics

Columbia University

New York, NY 10027

—————————————

Begin forwarded message:

Date: February 11, 2015 at 7:06:10 AM EST

From: Nora Brambilla <nora.brambilla AT ph.tum.de>

To: zajc AT nevis.columbia.edu

Cc: nora.brambilla AT ph.tum.de

Subject: 1502.02730

Dear Authours of 1502.02730,
I was seeing and reading with pleasure your big opus! Let me congratulate with you for this Hot QCD White Paper that I hope will have a large and positive impact for our research. Precisely because I hope that this document will have a positive impact
on the development of our field I am writing you to insert some changes that will improve the text.
In particular I have some relevant comments about the text that you have written on quarkonium dissociation that calls for some revision along the lines given below:

1) at very bottom of pag. 31 you say that the study of quarkonia in matter is carried on with lattice (first principle) and with models.
This is not true, such study is carried on with lattice and with effective field theories of QCD and then on a phenomenological level with models.
Plaese improve that paragraph.


2) top of pag. 32 you speak about the free energy and then abouts its use in a Schrodinger eq.
It has been recently shown ( Phys.Rev. D82 (2010) 074019, : arXiv:1007.5172) (using QCD at small coupling, i.e.  effective field of QCD at small coupling) that the free energy is not the  quark-antiquark potential at finite T. There is no reason for which this result should change at large coupling. So there is
no reason to use the free energy as a potential in a schrodinger eqiation.
This is the latest status and should be reported.


3)in the third paragraph of 32 starting with "Lattice computations also"
you say:
"In the bottomonium sector one can additionally utilize nonrelativistic
heavy quark effective theory [183]"
183 is a lattice calculation of the spectrum. They do do not use heavy quark effective theory but they use nonrelativistic QCD. In particular  they compare their lattice result to our calculations of the thermal bottomonium spectrum made with potential nonrelativistic QCD in
JHEP 1009 (2010) 038 : arXiv:1007.4156
(at small coupling in he continuum) and they find agreement with us.
The sentence should be modified and our reference added.


3) when in the last part of pag. 32 you listed the approached used to obtain the quark antiquark in medium potential you cannot leave out the effective field theory approach that was the FIRST one obtaining  the imaginary part in the potential. You quoted only [191] but these are lattice calculations of Wilson loop that tried to find on the lattice an imaginary part of the potential using the Wilson loop after the
work done in:
--first in one particular case using the Wilson loop in
JHEP 0703 (2007) 054 hep-ph/0611300
--and then in general in all the dynamical situations in an effective
field description   Phys.Rev. D78 (2008) 014017  arXiv:0804.0993



Again I would like to thank you for working at such formidable document that will serve well our field, I hope to have contributed my little part to it with this email ;-)

with my warmest regards and greetings
nora Brambilla

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