Global hyperon polarization in Au+Au collisions at sNN=27GeV in the STAR experiment

Abstract

Abstract The Quark-Gluon Plasma (QGP), appearing in non-central nucleus-nucleus collisions is generated with large orbital angular momentum. Spin-orbit coupling aligns spin directions of produced particles with the system angular momentum, through the creation of local vorticity. Properties of hyperon weak decays lead to the way of measuring polarization, that reflects vorticity. The global polarization of Λ and Λ ¯ hyperons was measured for Au+Au collisions at s N N = 7.7 − 200 GeV recorded with the STAR at the RHIC. However, different theoretical approaches are still in need of new experimental input to describe global polarization properly. That’s why it is important to measure the global polarization of different particle species. In this paper, we will report new results of hyperon global polarization ( P Λ + Λ ¯ and P Ξ − + Ξ ¯ + ) measurement via different methods for high-statistics Au+Au collisions at s N N = 27 GeV .