Title: Collision energy and system size dependence of longitudinal flow de-correlation at RHIC

PAs:  Gaoguo Yan, Zhenyu Chen, Shengli Huang, Jiangyong Jia, Michael Lisa, Xiaoyu Liu, Maowu Nie, Li Yi

Contact information: gaoguo.yan@outlook.com

Target journal: PRL

Talks in PWG meeting:
     https://drupal.star.bnl.gov/STAR/system/files/DeCorr27GeV20191016.pdf

     https://drupal.star.bnl.gov/STAR/system/files/DeCorr27GeV20191023.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20200916_decorrSummary_0.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20210414_isobar_FCV.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20210609_isobar_FCV.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20211110_isobar_FCV.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20220112_19p6_FCV.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20220713_19p6_FCV.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20221221_200_FCV.pdf

     https://drupal.star.bnl.gov/STAR/system/files/20240529_FCV.pdf

Talks in Collaboration meeting:

    https://drupal.star.bnl.gov/STAR/system/files/20211009_isobar_correct_collab.pdf

    https://drupal.star.bnl.gov/STAR/system/files/20220216_19p6_isobar_collab.pdf

    https://drupal.star.bnl.gov/STAR/system/files/20220914_200_19p6_collab.pdf

    https://drupal.star.bnl.gov/STAR/system/files/20231017_200_collab_0.pdf

Preliminary figures:

          https://drupal.star.bnl.gov/STAR/blog/gyan/Final-preliminary-plots-Quark-Matter-2022

Abstract:
                        

Motivation:
The ATLAS Collaboration published longitudinal flow de-correlation in Pb+Pb collisions at sqrt(s_NN) = 2.76 and sqrt(s_NN) = 5.02TeV and Xe+Xe collisions at \sqrt{s_{NN}}=5.44TeV.
While there is no experimental measurement of longitudinal flow de-correlation in RHIC energies. RHIC has Beam Energy Scan program, the energy from 7-200GeV and various collision species, Au+Au, Zr+Zr, Ru+Ru, U+U and so on. We present measurements of longitudinal flow de-correlation in Au+Au collisions at sqrt(s_NN) =200, 54.4, 27 and 19.6GeV to study collision energy dependence. We present measurements of longitudinal flow de-correlation in isobar and Au+Au collisions at sqrt(s_NN) =200 to study system size dependence.

Figures:

     Figure 1:

Fig.1: The  r_n(eta)(n=2,3) compared between the Au+Au collisions at  sqrt(s_NN) = 19.6 (black), 27 (red), 54.4 (blue) and 200 (pink) GeV in centrality bins: 0-10% and 10-40%. For r_2(eta)  (top panels),   3.1 < |eta_ref| < 5.1 (3.1 < eta_ref < 4.0 ) is selected in 19.6, 27 and 200 GeV (54.4GeV). For r_3(eta) (bottom panels), 2.1 < |eta_ref| < 5.1 (2.5 < eta_ref < 4.0 ) is selected in 19.6, 27 and 200 GeV (54.4GeV). The error bars and shaded boxes are statistical and systematic uncertainties, respectively.

    Figure 2: 

Fig.2: The r_n(eta/y_beam)  (n=2,3) compared between the Au+Au collisions at  sqrt(s_NN) = 19.6 (black), 27 (red), 54.4 (blue) and 200 (pink) GeV in centrality bins: 0-10% and 10-40%. For r_2(eta)  (top panels),  3.1 < |eta_ref| < 5.1 (3.1 < eta_ref < 4.0 ) is selected in 19.6, 27 and 200 GeV (54.4GeV). For r_3(eta) (bottom panels),  2.1 < |eta_ref| < 5.1 (2.5 < eta_ref < 4.0 ) is selected in 19.6, 27 and 200 GeV (54.4GeV). The error bars and shaded boxes are statistical and systematic uncertainties, respectively.

    Figure 3:

Fig.3: The r_n(eta)(n=2,3) (n=2,3) compared between the Zr+Zr (red), Ru+Ru (blue) and Au+Au (black) collisions at  sqrt(s_NN) = 200 GeV in centrality bins: 0-10% and 10-40%.  For r_2(eta)  (top panels),  3.1 < |eta_ref| < 5.1  is selected.  For r_3(eta) (bottom panels),  2.1 < |eta_ref| < 5.1 is selected. The error bars and shaded boxes are statistical and systematic uncertainties, respectively.

Summary:

Measurement of longitudinal flow de-correlation in isobar(Zr+Zr and Ru+Ru) collisions at 200 GeV and AuAu collisions at 19.6, 27, 54.4, 200 GeV.
1).The r_n(eta) decrease linearly with eta 

2).The r_2(eta) shows centrality dependence, but  no centrality dependence for r_3(eta)

3).Lower collisions  energy has larger longitudinal flow de-correlation

4).For  r_2(eta): small system size has larger longitudinal de-correlation

5).For r_3eta) :  No clear system size dependence