STAR HardProbes PWG

[沈丹丹 <shendandan AT mail.sdu.edu.cn>]

Hello HP-working group,

I intend to submit an abstract for QM 2023.

The title is "Measurements of $J/\psi$ polarization in Ru+Ru and Zr+Zr collisions at $\sqrt{s_{NN}} = 200$ GeV from STAR experiment ".

abstract: 

$J/\psi$ is an important probe to study the properties of the quark-gluon plasma (QGP) created in heavy-ion collisions.  A strong suppression of $J/\psi$ and zero $J/\psi$ $v_{2}$ have been observed in the isobar collisions system at RHIC-STAR experiment, which indicates a strong coupling of $J/\psi$ and QGP and limited regeneration effect.  Beside $J/\psi$ nulcear modification factor and $J/\psi$  azimuthal anisotropy observable, the $J/\psi$ polarization could be a new degree of studying QGP properties and $J/\psi$ production mechanism in heavy-ion collisions.  Moreover, it has been hypothesized that $J/\psi$ can be polarized by different mechanism, such as the spin-orbit coupling of $J/\psi$ and QGP's large angular momentum produced in non-central heavy-ion collisions and the early production of $J/\psi$ could makes its polarization sensitive to the strong magnetic field produced in early stage. 

In this talk, we will present the first $J/\psi$ polarization measurement of in a heavy-ion collision in RHIC energy.  The $J/\psi$ polarization results in the Helicity frame, Collins-Soper frame as well as the polarization with respect to the event-plane in Ru+Ru and Zr+Zr at $\sqrt{s_{NN}} = 200$ GeV will be present and its physics implications will also be discussed.

PDF version can be find in this link: https://drupal.star.bnl.gov/STAR/system/files/QM2023_abs_DandanShen_0.pdf

Best,

Dandan