Chirality, Polarization, and Vorticity in heavy-ion collisions

The strong magnetic field generated in non-central heavy-ion collisions could create an electric current with non-zero axial charge, due to so-called Chiral Magnetic Effect (CME). Searching for such possible chiral phenomena has been actively performed at both RHIC and LHC, but the measurements are likely dominated by the background such as the elliptic flow in conjunction with local charge conservation. A lot of studies are ongoing, e.g. by improving the analysis technique to reduce and possibly disentangle the background effect and by investigating p+A collisions where the magnetic field is randomly oriented unlike A+A collisions and therefore one does not expect the CME. A global rotation of the system is also closely related to the chiral phenomena, e.g. Chiral Vortical Effect. The global polarization of $\Lambda$ hyperons was observed for Au+Au collisions at $\sqrt{s_{NN}} = 7.7 — 200$GeV at RHIC, indicating the system vorticity. The global polarization might differ between particles and antiparticles, due to the opposite sign of the magnetic moments, which could be a direct tool to study the magnetic field in heavy-ion collisions. In this talk, the current status of the CME search in heavy-ion collisions will be presented. Recent results on global and local polarization caused by anisotropic flow will be also presented.