Remarks on possible local parity violation in heavy ion collisions

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.