STAR Correlations and Fluctuations PWG

[EsumiShinIchi <esumi.shinichi.gn AT u.tsukuba.ac.jp>]

Dear Ke, Nu and all
Thank you very much for the explanation, I now see the reason/difficulty 
and agree with the decision and the next steps. One more question, did 
we (Ke) try to test with the model like UrQMD that might have some 
reasonable baseline information such as the one coming from baryon 
conservation etc, which would give some wide suppression in small 
q space? Thanks again for the nice work. 
Best regards, ShinIchi

> 2024/11/29 6:40、Nu Xu <nxu AT lbl.gov>のメール:
> 
> Hi ShinIchi and All,
> 
> Let me give you the reasons from my side:
> 1) The data showed in Ke’s slides are from 200 GeV isobar collisions. As 
> you can see in slide 15, there is a black-dashed line labeled Baseline. 
> This baseline, as far as I understand, is from a kind of arbitrary Gaussian 
> term in order to have reasonable result from the Lednick´y and Lyuboshitz 
> (LL) fit. In this case, the result of the LL fit gives a positive value of 
> the scattering length, f0 > 0. The baseline was used in STAR  Lambda-Lambda 
> correlation function from Au+Au collisions and ALICE’s publication for 
> Lambda-Lambda correlation functions from p+p and p+Pb collisions. So far, 
> there is no physics  justification for the baseline;
> 
> 2) In STAR’s previously published Lambda-Lambda from 200 GeV Au+Au 
> collisions (Phys.Rev.Lett. 114, 022301(2015)), the resulting of the LL fit 
> was negative value of the scattering length, f0 < 0, which has been 
> criticized by colleagues mostly from ALICE. Part of the reason for the 
> negative value of the scattering length is due to the treatment or 
> no-treatment of the resonance decays, according to theory analysis 
> (Phys.Rev. C91, 024916 (2015)).
> 
> In my view, we should understand the source of the baseline, apply it to 
> both Isobar and Au+Au collision data and provide final answer on the nature 
> of the scattering length f0. Perhaps we should make a joint analysis of the 
> extra Gaussian term, as a function of collision centrality, transverse 
> momentum and unified test on the decay contributions. Then a combined fit 
> could be the final result. 
> 
> The result of the Lambda-Lambda correlation function is important as it 
> will not only offer information on strange baryon interactions but may also 
> be related to the existence of the H-dibaryon. Let us focused on the 
> analysis and get the right final result before going public. 
> 
> Best regards,
> 
> Nu
> 
>> On Nov 28, 2024, at 9:58 AM, EsumiShinIchi 
>> <esumi.shinichi.gn AT u.tsukuba.ac.jp> wrote:
>> 
>> Dear Ke, Nu and Hanna 
>> Since I did not say much about this, I would like to ask one question, 
>> why did you/we decide to exclude just "Lambda-Lambda” results? Is 
>> that because we don’t yet know much about the baseline? Then what 
>> about removing the baseline curve? and just showing the correlation data?, 
>>  
>> would that be OK?, if you think correlation data is close to final and 
>> will not 
>> change in the future, as this is anyway internal workshop for the 
>> discussion 
>> and we ask all these theorists to consider the results might not yet be 
>> public.  
>> But of course, I would respect your decision to choose which results 
>> to show and discuss in the workshop. Thanks again for the nice work. 
>> Best regards, ShinIchi
>> 
>> PS : Could you please remind me how you define your baseline (dashed 
>> black curve) in page 15? There was a suggestion to show this baseline 
>> curve in orange or green color to make it more visible that it is 
>> overlapping 
>> with LL fit and data above ~80MeV/c, which sounds reasonable. 
>> 
>>> 2024/11/28 21:01、K.Mi <star-cf-l AT lists.bnl.gov>のメール:
>>> 
>>> Dear All, 
>>> 
>>> As discussed last week, I’d like to discuss the slide I’m going to 
>>> present in BESII Workshop. Here’s the link: 
>>> https://drupal.star.bnl.gov/STAR/system/files/20241204_BESII_Workshop_kmi_v0.pdf
>>> 
>>> Thank you.
>>> Best regards,
>>> Ke
>>> 
>>>> 2024年11月28日 18:28，姜夏蕾 (via star-cf-l Mailing List) 
>>>> <star-cf-l AT lists.bnl.gov> 写道：
>>>> 
>>>> Dear Nu and Hanna,
>>>> 
>>>> As scheduled last week, I will give a brief presentation, please find my 
>>>> slides in this link:
>>>> https://drupal.star.bnl.gov/STAR/system/files/lightnuclei_cf_pwg_1128.pdf
>>>> 
>>>> Best regards,
>>>> Xialei
>>>> ------------------ Original ------------------
>>>> From:  "STAR Correlations and F"<star-cf-l AT lists.bnl.gov>;
>>>> Date:  Wed, Nov 27, 2024 02:27 PM
>>>> To:  "STAR Correlations and F"<star-cf-l AT lists.bnl.gov>; 
>>>> Subject:  [[Star-cf-l] ] 回复： CF PWG meeting, November 28st, 2024
>>>>  Dear Nu and Hanna,
>>>> 
>>>> If time permits, I would like to give an update about the paper proposal 
>>>> of measurement of p-Xi correlation function in 200 GeV nuclear 
>>>> collisions.
>>>> 
>>>> Best regards,
>>>> Boyang
>>>> 
>>>> STAR Correlations and Fluctuatio<star-cf-l AT lists.bnl.gov> 在 2024年11月26日 
>>>> 周二 1:53 写道：
>>>> Dear CF Folks,
>>>> We invite you to join the weekly STAR CF-PWG meeting on Thursday, 
>>>> November,  28th, 2024:
>>>> Time: 9:00 am (EDT), 3:00 pm (CET), 7:30 pm (India), 10:00 pm (China)
>>>> Please try to post your slides at your earliest convenience, preferably 
>>>> at least one day before the meeting.
>>>> We will connect via Zoom:
>>>> Zoom link: 
>>>> https://urldefense.com/v3/__https://cern.zoom.us/j/67357482915?pwd=NTEzV0lJc2o1UDRoMVMzQnk0YTBxUT09__;!!P4SdNyxKAPE!HWZXgKhKWUv30pq50JK7OeX5kN8XslYLSUruKrQ0JcI5TywqldYa8Ln4dF7-1vh7A380GZ7SgUrKkrPJTSk$
>>>>   // Passcode: 246711
>>>> 
>>>> Group Meeting Website: 
>>>> https://drupal.star.bnl.gov/STAR/blog/luoxf/correlations-and-fluctuations
>>>> 
>>>> Preliminary Plots Website: 
>>>> https://drupal.star.bnl.gov/STAR/blog/gos/correlations-and-fluctuations-preliminary-plots
>>>> 
>>>> This week, those of us who don’t celebrate Thanksgiving will continue 
>>>> the discussion regarding QM contributions.
>>>> If you have any additional topics you’d like to include in the 
>>>> discussion, please let us know.
>>>> We look forward to seeing you all next Thursday.
>>>> 
>>>> Kind regards,
>>>> Nu and Hanna
>>>> 
>>>> 
>>>> prof. dr hab. inż. Hanna Zbroszczyk
>>>> E-mail: hanna.zbroszczyk AT pw.edu.pl
>>>> Tel: +48 22 234 5851 (biuro)
>>>> 
>>>> Adres:
>>>> Poltechnika Warszawska
>>>> Wydział Fizyki
>>>> Zakład Fizyki Jądrowej
>>>> ul. Koszykowa 75
>>>> Biuro: 117b (via 115)
>>>> 00-662 Warszawa
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>> 
>