Remarks on possible local parity violation in heavy ion collisions

TL;DR

This paper discusses potential signs of local parity violation in heavy ion collisions, analyzing correlation data and its implications for the chiral magnetic effect, suggesting a significant parity-violating component.

Contribution

It provides a detailed analysis of correlation measurements, highlighting the possible magnitude of parity violation and its consistency with the chiral magnetic effect in heavy ion collisions.

Findings

Correlations are mainly in-plane, not out-of-plane.

Parity violating component could be as large as background.

Signal dependence on transverse momentum aligns with chiral magnetic effect expectations.

Abstract

In this note we discuss some observations concerning the possible local parity violation in heavy ion collisions recently announced by the STAR Collaboration. Our results can be summarized as follows (i) the measured correlations for same charge pairs are mainly in-plain and not out of plane, (ii) if there is a parity violating component it is large and, surprisingly, of the same magnitude as the background, and (iii) the observed dependence of the signal on the transverse momentum (p_t) is consistent with a soft boost in p_t and thus in line with expectations from the proposed chiral magnetic effect.