STAR Correlations and Fluctuations PWG

[apandav <apandav AT rcf.rhic.bnl.gov>]

Dear Xiaofeng,

Thanks a lot for the comments and suggestions. I have made the suggested 
changes except for the ones listed below.
Please find the updated draft on the below link.
https://drupal.star.bnl.gov/STAR/system/files/pos_CPOD_C56_pa_e3.pdf

>     1. Line 16, We measured net-charge, which is not net-particle.
We measure net-charge in terms of net-charged particles. In STAR's 
net-charge PRL paper,
they obtain net charges as "difference between the number of positive 
and negative charged particles on an event-by-event basis." For example, 
we did not multiply charge of 2 for doubly charged positive particle in 
net-charge calculation but simply identified whether the particle has 
charge and then constructed net-charge. So I have kept it same as 
before.


>     7. Line 79-83 and in summary Line 111-114, it is stated that this
> increasing negative values for C6/C2 is consistent with cross-over
> nature from Lattice and FRG
>     calculations.  Based on current wide centrality bin 0-40% and
> limited statistics, this statement is too strong, even stronger than
> the submitted C6 paper.
>         1) in our submitted  C6 paper, we state that 27 GeV (Run 18)
> and 54.4 GeV C6/C2 is consistent with zero, where the deviation
> significance is stronger than current
>             measurement (27 GeV with Run 11 with less statistics) and
> also current claim is based on 0-40% wide centrality bin.
>         2) This statement is contradict with the statement in Line
> 32-33, the non-monotonic behavior consistent with calculations that
> included a critical point.
>
>     Please rephrase the statement accordingly.  We may just quantify
> the significance of deviations within the energy range we studied.

I agree with the second point regarding the non-monotonic observation, 
that this might be a concern and hence I have removed statements on 
lattice comparisons. But regarding your first point, I have few 
arguments to mention although I have removed statements on cross-over 
from both the places.

Regarding the submitted C6 paper, the inference is drawn only for 200 
GeV which is as follows:
"Lattice QCD calculations, with T = 160 MeV and μB = 0-110 MeV, predict 
the negative value of C6/C2 ∼ −1.5, which is qualitatively consistent 
with the experimental results of central Au+Au collisions at top RHIC 
energies. These new measurements are statis-tics limited and seem to 
favor a smooth crossover for the QGP-hadronic matter transition."

The exact statement that is mentioned in previous CPOD draft's summary 
is:
"The net-proton C6/C2 for the same centrality show increasingly negative 
values with
decreasing collision energy at a level of ≤2σtot which is qualitatively 
consistent with the sign and energy-dependence trend predicted by 
lattice-QCD and FRG model calculations for net-baryon fluctuations with 
crossover being the nature of phase transition in their calculations."

Here I take inference from the energy dependence trend of C6/C2, I talk 
about the systematically increasing negative trend of C6/C2 towards 
lower energy, which also lattice and FRG predicts: that the C6 becomes 
more negative with larger muB or small energy. We have mentioned that 
measurements are for 0-40% centrality , that it is a <2 \sigma effect 
and also cautioned the reader to keep in mind the limitations when 
comparing to lattice. We reported what we find in our measurements. That 
the data's sign and energy trend for net-proton is consistent with trend 
predicted by lattice and FRG for net-baryon. We did not claim crossover, 
while in the C6 paper we do mention that "the data favours crossover at 
top RHIC energy". Hence, I think my statements were not too strong, 
although now it has been removed as per your suggestion.

Let me know your thoughts.

Best regards,
Ashish

> > Dear star-cf-l AT lists.bnl.gov members,
> >
> > Ashish Pandav (apandav10 AT gmail.com) has submitted a material for a 
> > review,
> > please have a look:
> > https://drupal.star.bnl.gov/STAR/node/56233
> >
> > ---
> > If you have any problems with the review process, please contact
> > webmaster AT www.star.bnl.gov
> > ______________________________