Vorticity and Spin Polarization in Heavy Ion Collisions: Transport Models

Understand

Heavy ion collisions generate strong fluid vorticty in the produced hot quark-gluon matter which could in turn induce measurable spin polarization of hadrons.

• We review recent progress on the vorticity formation and spin polarization in heavy ion collisions with transport models.
• We present an introduction to the fluid vorticity in non-relativistic and relativistic hydrodynamics and address various properties of the vorticity formed in heavy ion collisions.
• We discuss the spin polarization in a vortical fluid using the Wigner function formalism in which we derive the freeze-out formula for the spin polarization.