STAR Correlations and Fluctuations PWG

[William Llope <fr4526 AT wayne.edu>]

hi again xiaofeng and all,
i've added references to talks by K. Mi & J. Ball at QM22 and C. Fu at QPT21 
to
the summary slide. I also set the y-axis range in the 2 projections in the 
right column of
slides 10,11,12 to be the same for clarity - i think it helps. Please find 
version 7 available here:
https://drupal.star.bnl.gov/STAR/presentations/BES-Tea-Seminar-5202022/Correlations-and-fluctuations-STAR
thanks, cheers
bill

> On May 18, 2022, at 12:43 PM, William Llope via Star-cf-l 
> <star-cf-l AT lists.bnl.gov> wrote:
> 
> Hello Xiaofeng,
> 
>> On May 17, 2022, at 6:59 PM, Xiaofeng Luo <xfluo.star AT hotmail.com> wrote:
>> 
>> Hi Bill,
>> 
>>    Very nice talk !
>>    Please find my comments and suggestions below : 
>> 
>>    General comments : 
>>    1. Since this seminar is on behalf of STAR on topic of Correlation and 
>> Fluctuations, I feel it is Inappropriate that 
>>        a lot of STAR results are missing, such as p-p, p-d, d-d 
>> femtoscopic correlation just shown in QM2022,
>>        BES-I and 3 GeV higher-order fluctuations. 
> 
> i will mention these results and add the references to the slides
> 
>>    2. It is very unusual to me that we present new preliminary results at 
>> a seminar, not a conference.
> 
> i'll take this as a comment. 
> 
>>   Details : 
>>    1. Currently, for the new preliminary results at 3 GeV, there are small 
>> dip at Delta_phi ~ 0 for p-d and d-d pairs., and not seen in other pairs. 
>>        Could you explain this ? 
> 
> yes - it is very interesting. Track crossing is very small for these pairs, 
> and of course
> we correct for that small amount, so this is not crossing. that is a true 
> SRC effect
> that deserves further investigation, as i will point out. It is one of the 
> interesting observations
> from this slide for sure. I do not intend to speculate on the physics 
> interpretation
> of it in this talk. Thanks for noticing it!
> 
>>    2. Could you explain, why the d-t pair show larger enhancement ~ 48% 
>> than d-d ~ 24% and t-t ~ 36% ?
> 
> These are the experimental results. The shape of these correlations
> suggest a clan-like or "multifragmentation" process where "clusters"
> outflow and break up in flight, causing near-side intermediate range
> positive correlations. 
> Remember that these percentages are values of R2.
> Which means, formally, that there are about 25% more dd pairs
> moving in similar directions in the event ensemble than can be explained 
> on the basis of the single particle spectra of d's in those same events.
> Near side is enhanced and far side is depleted because of the
> kinematic focussing of the decay products from these flowing clans.
> This is a very old picture for multifragmentation - i used the same picutre
> when i was at the NSCL in the 90's.
> 
>>    3. In the summary, It is stated that those strong correlations are 
>> coming mainly from a spectator source     
>>        I think it can be more specific : the enhancement could be mainly 
>> due to nuclear fragmentation, but it needs further investigation.
> 
> i don't ascribe any real difference in meaning to those two terms.
> I mean 'spectator source' in the sense of the simple participant spectator
> model (from gary westfall and collaborator's "firestreak" model at the 
> bevalac).
> anyway, i consider "nuclear fragmentation" to be an equivalent term to 
> "spectator source" - more or less - and i'll happy to mention your terms 
> also
> in the talk. cheers
> bill
> 
>> 
>> 
>> Thank you, 
>> Best Regards,
>> Xiaofeng
>> 
>> On 2022/5/17 04:47, William Llope via Star-cf-l wrote:
>>> hi all - i remain eager to address your comments on my presentation 
>>> (which is this friday, 5/20, at 10am).
>>> thanks, cheers
>>>     bill
>>> 
>>> 
>>>> On May 9, 2022, at 3:41 PM, webmaster--- via Star-cf-l 
>>>> <star-cf-l AT lists.bnl.gov>
>>>> wrote:
>>>> 
>>>> [EXTERNAL]
>>>> 
>>>> Dear 
>>>> star-cf-l AT lists.bnl.gov
>>>> members,
>>>> 
>>>> W.J. Llope (
>>>> wjllope AT wayne.edu
>>>> ) has submitted a material for a review, please
>>>> have a look:
>>>> 
>>>> https://drupal.star.bnl.gov/STAR/node/59591
>>>> 
>>>> 
>>>> ---
>>>> If you have any problems with the review process, please contact
>>>> 
>>>> webmaster AT www.star.bnl.gov
>>>> 
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>> 
>> -- 
>> Xiaofeng Luo
>> Professor of Physics
>> College of Physical Science and Technology
>> Central China Normal University
>> Luoyu Road 152, Wuhan China
>> Office Phone #: +86-27-67867500
>> 
> 
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