ALICE probes of local parity violation with charge dependent azimuthal correlations in Pb-Pb collisions

TL;DR

This paper presents measurements of azimuthal particle correlations in Pb-Pb collisions at the LHC to investigate potential local parity violation effects in strong interactions, providing constraints on background and signal mechanisms.

Contribution

It introduces new three-particle correlator measurements sensitive to charge separation related to local parity violation in heavy-ion collisions.

Findings

Three-particle correlator indicates possible charge separation effects.

Correlations vary with collision centrality, pseudorapidity, and transverse momentum.

Results constrain models of local parity violation and background effects.

Abstract

We report on the measurement of two and three particle azimuthal correlations in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV recorded with ALICE at the LHC. While two particle azimuthal correlations mainly provide an important information on possible background correlations, the three particle correlator probes the charge separation of hadrons with respect to the collision reaction plane which is expected for local parity violation in strong interactions. The two and three particle correlations are presented as a function of collision centrality and differentially vs. pseudorapidity and transverse momentum, and provide strong constraints on the possible mechanism of background (parity conserving) and signal (parity odd) effects in heavy-ion collisions.