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["Fisyak, Yuri V" <fisyak AT bnl.gov>]

Hi Sooraj,   in new model for dE/dx I have allowed to use 2 pads clusters. In the old model they were rejected. This slightly increases dE/dx efficiency without any significant damage of the dE/dx resolution.

1. Non Gaussian nsigma_e distributions (https://drupal.star.bnl.gov/STAR/system/files/nsigmaeCorr.pdf):

1. I don’t know what do you call “corrected” nsigma_e. 
2. I know that with new dE/dx model I have momentum dependence overestimation for electrons with respect to the model up to 10%. The electron dE/dx is a special beast and it requires a special treatment.
3. Log(dE/dx) has much better match with Gaussian than dE/dx (which is Landau distribution with infinite dispersion) due to the finite dispersion and the Central Limit theorem, but it is not exactly Gaussian. How close it to Gaussian depends on resolution and statistics.

Acceptance (https://drupal.star.bnl.gov/STAR/system/files/LightNucleiFlowWithEfficiency_Yue20231129.pdf)

1. I don’t know that do you mean by “We used the nsigma cut (proton) / z cut (light nuclei)”.
2. What is “z cut” ? I don’t understand what  is acceptance plotted on slide 8.

I suggest for Yue Xu and Wei Zhang to bring these issues to TPC meeting and discuss them there.

 

 

 

                                                              Yuri Fisyak

STAR                                           Phone: +1 631 344 3913
Brookhaven National Laboratory  Fax:    +1 631 344 4206
510A/1-161
http://www.star.bnl.gov/~fisyak       E-mail: fisyak AT bnl.gov

 

 

 

From: Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov>
Date: Monday, December 4, 2023 at 5:14 PM
To: Van Buren, Gene <gene AT bnl.gov>, Fisyak, Yuri V <fisyak AT bnl.gov>, geurts AT rice.edu <geurts AT rice.edu>
Cc: Barbara Trzeciak <barbara.trzeciak AT gmail.com>, 张炜 <wzhang AT m.scnu.edu.cn>, Ma, Rongrong <marr AT bnl.gov>, Mooney, Isaac <isaac.mooney AT yale.edu>, Yi Yang <yiyang AT ncku.edu.tw>, nihar AT rcf.rhic.bnl.gov <nihar AT rcf.rhic.bnl.gov>, xuyue <xuyue AT impcas.ac.cn>, subhash <subhash AT rcf.rhic.bnl.gov>, Tribedy, Prithwish <ptribedy AT bnl.gov>, Zhenyu Chen <zhenyuchen AT sdu.edu.cn>, Yiding-Han AT rice.edu <Yiding-Han AT rice.edu>
Subject: Some issues with SL23d and SL23e productions

Hi Gene, Yuri, All,

   During last weeks PWG meetings a couple of issue regarding the new SL23d and SL23e production were shown. 

 

Wei Zhang showed at the HP PWg meeting that the SL23d production has considerable deviation from Gaussian distribution for nsigma_e distributions. This is less pronounced in SL21c (previous production). Please find the slides here where he compares them for 14.6 GeV (slides 3-8) https://drupal.star.bnl.gov/STAR/system/files/nsigmaeCorr.pdf. The deviation is more pronounced at high pT, but can also see at lower pT. Let us know if you have any insights on what could be causing this  

 

Yiding, do you remember seeing such deviations when you looked at the SL23d production? I believe you did look at the SL23d production with the fix for the low pT dE/dx issue.

 

Separately, Yue Xu showed at the FCV meeting that the acceptance for He3 is different in SL23d and SL23e, and with SL23e the acceptance for triton and He3 are inconsistent. He sees that with and without m2 cuts. See S8 here https://drupal.star.bnl.gov/STAR/system/files/LightNucleiFlowWithEfficiency_Yue20231129.pdf

 

Let us know if you need to see further details and your thoughts 

 

thanks

Sooraj

--

Sooraj Radhakrishnan

Research Scientist,

Department of Physics

Kent State University

Kent, OH 44243

Physicist Postdoctoral Affiliate

Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road

Berkeley, CA 94720

Ph: 510-495-2473

Email: skradhakrishnan AT lbl.gov