Date : March 22, 2022, 16:00 CET
Derek Teaney (Stony Brook University)
Link: https://zoom.us/j/98260147834?pwd=VW5BQStqUGUrUFFzWG1jL2tuWXJoZz09
Title: Soft pions, hydrodynamics, and the chiral critical point
Abstract:
I will first discuss chiral symmetry breaking and the evidence for the O(4) critical point from lattice QCD. With this motivation, I will then describe the appropriate hydrodynamic theory well below the critical temperature, where soft pion Goldstone modes are coupled to the conserved charges of the O(4) symmetry. Well above the critical temperature, the hydrodynamic theory is simply ordinary hydrodynamics. Close to the critical temperature, the order parameter is added to the list of hydrodynamic fields. I will describe simulations of the critical region, using the stochastic hydrodynamic theory including the order parameter, which determine the correct static and dynamic critical exponents, and gracefully transitions between the two hydrodynamic theories above and below the critical temperature. Finally, I review measurements of soft pions in heavy ion collisions, and point out that yield of soft pions is enhanced relative to the expectations of ordinary hydrodynamics. I suggest that this enhancement is a natural consequence of the O(4) critical dynamics.
