Charge separation relative to the reaction plane in Pb-Pb collisions at $\sqrt{s_{\rm NN}}= 2.76$ TeV

TL;DR

This paper reports measurements of charge-dependent azimuthal correlations in Pb-Pb collisions at 2.76 TeV, revealing a charge separation relative to the reaction plane that is consistent across different collision energies, offering new insights into the underlying physics.

Contribution

The study provides the first detailed measurement of charge-dependent azimuthal correlations at LHC energies, extending previous RHIC results and enhancing understanding of charge separation phenomena.

Findings

Charge-dependent azimuthal correlations are observed.

The charge separation signal shows little energy dependence.

Results suggest similar underlying mechanisms at RHIC and LHC energies.

Abstract

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.