Hi, Peter

Thanks for the further suggestions.
We've incorporated them into the updated draft:
http://www.star.bnl.gov/protected/bulkcorr/rexwg/flow/Parity/BES/PRL/ver12/LPV_BES12.pdf

Please find detailed replies inline.

Gang Wang
Department of Physics & Astronomy
UCLA

----- Original Message -----
> From: "Peter Seyboth" <pxs@mppmu.mpg.de>
> To: "Gang Wang" <gwang@physics.ucla.edu>
> Cc: "STARpapers" <starpapers-l@lists.bnl.gov>
> Sent: Thursday, March 27, 2014 6:48:24 AM
> Subject: Re: [Starpapers-l] Reply to collaboration review -- Beam energy dependence of charge separation along the
> magnetic ?eld in Au+Au collisions at RHIC
> 
> Hi,
> 
> Here I am again with some more remarks.
> 
> - in Eq.(1) it might bw better to use a symbol as
>    the charge index e.g. \alpha, as is done in most
>    of the published literature. Then say below the
>    equation ... and the subscript $\alpha$ (+ or -)
>                 denotes ...

PAs: Done.

> - could you justify why you can neglect the higher
>    orders in Eq.(1)

PAs: The charge separation across the reaction plane is 
a "directed dipole", in the sense that in each event 
(or domain) a_+ and a_- have opposite signs. Higher 
harmonics will put ambiguity to the direction.
Note the STAR paper PRC 81, 054908 (2010) has the following statement 
ˇ°ˇ­In this analysis we consider only the first harmonic coefficient a_{1}, 
which is expected to account for most of the effect, although higher 
harmonics determine the exact shape of the distributionˇ­ˇ± (p. 054908-4).

> - could you give the explicit relation between gamma
>    and the correlation term -<a_alpha a_beta>
> 
PAs: This was written out in line 8-10 below Eq(1).

> - Figs.2,3: propose to add a panel with the 200 GeV results.
>    These are included in Fig.4

PAs: The 200 GeV results have already been published a few times,
and we aim at a letter paper.
For the same reason we didn't plot the ALICE results.
The 8-panel figure can be found in our new White paper.

> - Fig.2, caption and related text: It is not clear what you
>    mean by "charge independent", you should be more precise.
>    What does the "charge independent" result look like for
>    the data ?

PAs: The charge independent results are the average of OS and SS.

> - when you first discuss Fig.2 in the text it would be helpful
>    to mention that the pure CME expectation is
>      gamma_++,-- = - gamma_+-
>    and that the deviation from this relation is attributed to
>    background.

PAs: For the issue about the symmetric OS and SS, 
it was the initial expectation of the experimental observable,
and then we saw gamma_OS is much smaller than gamma_SS in magnitude,
and thought it was due to quenching in the medium.
Later in the paper by Dhevan and me, we found the HBT+Coulomb effects,
and also the momentum conservation+v2 effect. 
In view of the complication of this issue, the PAs feel it's
hard to tell this history in a sentence or two. 
So for now we refrain from adding such discussion, and
in case the referees ask for this we may add one sentence
"The CME is expected to generate equal correlation magnitudes (opposite signs) for same and opposite charge pairs,
while charge independent backgrounds have the same contributions to both."

> - extraction of CME contribution (Eqs.3,4,5): if I understand
>    correctly you assume F to be the same for SS and OS. If this
>    is true, you should mention it and add the results for F
>    in Fig.4. This would give the reader some idea how big the
>    CME signal is with respect to the background.
> 
PAs: No, F is also charge dependent:
F = (gamma + delta)/(1+k*v2), or just roughly the sum of gamma and delta,
since v2 is far smaller than 1. The readers should be able to
figure that out if they are intereested.


> - with regard to eB and the pion mass I would say that field can
>    just as well influence the motion of protons or kaons. The
>    numerical equality of eB with m_pi^2 is a chance coincidence
>    without any physics reason. I still suggest to remove it. If
>    anything, you might discuss how much it can accelerate the
>    quarks to create the charge separation.
PAs: Now we changed it to 10^4 MeV^2.

> Lastly, it would be useful if you could compile the paper
> with line numbers. This facilitates the editorial work.
> 
> With best regards,   Peter