itle: Spin polarization effects in Heavy Ion Collisions
Presenter: Zuo-tang Liang (Shandong University)
In non-central high energy heavy ion collisions, the colliding system possesses a huge orbital angular momentum along the normal direction of the reaction plane. Due to the spin orbit interaction in the relativistic quantum system, such a huge orbital angular momentum leads to the spin polarization of quarks and anti-quarks in the quark matter system produced in the collision. Such an effect, known as the global polarization effect (GPE), was predicted many years ago and has been confirmed by the STAR collaboration at RHIC. The discovery of GPE by the STAR collaboration opens a new window in heavy ion physics in general and in studying the properties of quark-gluon plasma in particular. In this talk, I will briefly review the original ideas and calculations that lead to the prediction and summarize progresses and problems in related aspects.