Search for the chiral magnetic effect and vorticity-induced polarization effects in nuclear collisions

Abstract

Abstract In relativistic heavy ion collisions, the chiral magnetic effect, known as the “CME”, has been extensively searched for over a decade in order to gain insights into the chiral symmetry restoration in the Quark-Gluon-Plasma, the possible local strong parity violation, and the extremely strong magnetic field. Based on the magnetic field direction and its correlation with the reaction plane, the CME has been mostly measured via a charge-dependent azimuthal correlator with respect to the second-order event plane, where experimental results are not yet conclusive due to their dominant background contaminations. Recent experimental efforts from STAR, ALICE, and CMS Collaboration will be discussed in this paper. Moreover, the total angular momentum from a noncentral collision can induce many important effects via its coupling to the particles spin, e.g., Λ polarization, which provides essential information about properties of this strongly-interacting fluid-like medium. Besides the discovery of this exotic phenomenon, recent preliminary results from the STAR and ALICE experiment will be reviewed.