Estimation of P-odd correlators in heavy ion collisions at RHIC energies 62.4 -- 200 GeV

TL;DR

This paper investigates parity violation signals in heavy ion collisions at RHIC energies, analyzing correlator dependencies on energy and centrality, and compares experimental data with chiral magnetic effect model predictions.

Contribution

It provides a detailed analysis of P-odd correlators across different energies and centralities, and compares experimental results with theoretical chiral magnetic effect predictions.

Findings

Correlators increase with collision energy and centrality.

Experimental data at 62.4 GeV align with model predictions.

At 200 GeV, the model underestimates same charge correlators in central collisions.

Abstract

The strength of parity violation effect can be characterized by correlator value in the framework of local $\mathcal{TIP}$ hypothesis. The energy and centrality dependencies of correlators for same and opposite charges are discussed for heavy ion collisions in RHIC energy domain 62.4 -- 200 GeV. The magnetic field shows a significant increasing at initial energy decreasing for intermediate and large times. Two possible scenarios for initial time are investigated in detail. Both scenarios predict the most close values for initial time in ${Au+Au}$ collisions at 62.4 GeV. Disagreement between initial time values obtained for two various scenarios increases with energy increasing and for collisions of lighter ${Cu}$-nucleus. Boundary values for correlators related with possible local $\mathcal{TIP}$ violation are calculated in the framework of analytic approach of chiral magnetic effect for ${Au+Au}$ collisions at 62.4 and 200 GeV. The results are shown as function of collision centrality. Preliminary experimental STAR data are compared with predictions of chiral magnetic effect model directly. Experimental signals consistent with model expectations for both same and opposite charge correlations in ${Au+Au}$ collisions at 62.4 GeV at all centralities. At higher energy 200 GeV the model of chiral magnetic effect underestimates same charge correlator values for central and midcentral events but the same charge correlations for peripheral events as well as opposite charge correlations are in the boundaries predicted by model calculations.