Global polarization measurement in Au+Au collisions

This is the authors' abstract. We don't add key points for this paper.

The system created in noncentral relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Because of spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of {Λ} and Λ hyperon global polarization measurements in Au+Au collisions at √sNN=62.4 and 200 GeV performed with the STAR detector at the BNL Relativistic Heavy Ion Collider (RHIC). The observed global polarization of {Λ} and Λ hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |P_Λ,Λ|0.02, is compared with the theoretical values discussed recently in the literature.