STAR HardProbes PWG

[wy157543 AT mail.ustc.edu.cn]

Dear all, 

We plan to submit an abstract on ψ(2S) production in isobaric collisions.

The title is "psi(2S) production in isobaric collisions at 200 GeV with the STAR experiment"

Charmonium is an important probe to the properties of the quark-gluon plasma (QGP) created in heavy-ion collisions. Measurements from SPS, RHIC, and the LHC experiments show that charmonium production in heavy-ion collisions is an interplay of several effects, including dynamic dissociation and regeneration in QGP and cold nuclear matter effects. All these effects strongly depend on the binding energy of quarkonium state. The binding energy of $\psi(2\rm{S)}$ is significantly less than that of J/$\psi$, comparison of the suppression of J/$\psi$ and $\psi(2\rm{S})$ at RHIC can shed new light on the production mechanism of charmonium in QGP and the properties of the QGP. Measurement of J/$\psi$ suppression with high precision was achieved with 4B isobaric collisions ($^{96}_{44}Ru$ + $^{96}_{44}Ru$ and $^{96}_{40}Zr$ + $^{96}_{40}Zr$) at $\sqrt{s_\mathrm{NN}}$ = 200 GeV. This dataset provides an unique opportunity for the study of $\psi(2\rm{S})$ production in heavy ion collisions with good precision.

 

In this contribution, the first measurement of $\psi(2\rm{S})$ production in heavy ion collisions at RHIC will be presented. The J/$\psi$ and $\psi(2\rm{S})$ signals are reconstructed in isobaric collisions at $\sqrt{s_\mathrm{NN}}$ = 200 GeV via the $e^{+}e^{-}$ decay channel with machine learning technique. Centrality and transverse momentum dependence of the ratio of $\psi(2\rm{S})$ yield over that of J/$\psi$ will be shown and physics implication will be discussed.

PDF version can be find in this link:

https://drupal.star.bnl.gov/STAR/system/files/QM2023_v1.pdf

Best regards,

Yan