Speaker
Description
The search for the Chiral Magnetic Effect (CME) is ongoing in relativistic heavy-ion experiments. It is crucial to scrutinize the CME-sensitive observables to rule out non-CME contributions. Recently STAR has measured an unexpectedly large signal of global spin alignment ($\rho_{00}$) for $\phi$ meson, which is argued to be sensitive to the local fluctuations of the vector meson strong force field[1]. A finite $\rho_{00}$ of vector mesons can influence CME-sensitive observables. In particular, the $\rho_{00}$ of $\rho^0$ mesons can induce a positive (negative) contribution to the CME observables, depending on the deviation of $\rho_{00}$ being larger (smaller) than 1/3 [2,3]. In this talk, we will present measurements of the global spin alignment for $\rho^0$ meson as functions of transverse momentum and centrality in Au+Au and Isobar (Zr+Zr and Ru+Ru) collisions at $\sqrt{s_{NN}}$ = 200 GeV. We will discuss the implications of our results in the context of interpreting CME observables.
[1] M. S. Abdallah et al. (STAR Collaboration), Nature 614, 244 (2023).
[2] A. Tang, Chin. Phys. C 44, 054101 (2020).
[3] D. Shen, J. Chen, A. Tang, G. Wang, Phys. Lett. B 839, 137777 (2023).
