Local equilibrium and Lambda polarization in high energy heavy ion collisions

The polarization of the $\Lambda$ hyperon has become an important probe Quark-Gluon Plasma produced in relativistic heavy-ion collisions. Recently, it been found that receives a substantial contribution from local equilibrium term proportional to symmetric derivative four-temperature vector, thermal shear tensor. We show that, at very high energies, this can restore agreement between experimental measurements and predictions hydrodynamic model, provided hadronization hypersurface is isothermal. review theoretical derivation new term, discuss numerical computations RHIC LHC compare them with data. also present effect feed-down corrections.