# QM 2022

Apr 4 – 10, 2022
Auditorium Maximum UJ
Europe/Warsaw timezone

## Soft pions near the QCD chiral critical point: transport and dynamics

Apr 5, 2022, 4:50 PM
20m
medium aula B (Auditorium Maximum UJ)

### medium aula B

#### Auditorium Maximum UJ

Oral presentation QCD matter at finite temperature and density

### Speaker

Dr Eduardo Grossi (IPhT Saclay)

### Description

During the evolution of a heavy ion collision, the system passes close to the O(4) critical point. The order parameter that controls the chiral symmetry is the quark condensate $\langle \bar q q \rangle \sim \phi_a$. Due to the non-zero quark mass, there is a crossover (not a second order phase transition) between the high and low temperature phases. In this talk we will introduce the hydrodynamic theory with the order parameter as an additional hydrodynamical variable and show the results of the real time simulation of this model that shares the same universality class of QCD, the so-called Model G.

Due to the presence of the superfluid pion degrees of freedom, we compute the modification of the ordinary hydrodynamic transport coefficients and estimate the expected critical enhancement of soft pion yields, which provides a plausible explanation for the excess seen in experiment relative to ordinary hydrodynamic computations. We extract the dynamical critical exponent of $\zeta=1.47 \pm 0.01 ({\rm stat})$, which is compatible with the theoretical expectation of $\zeta = d/2$ (with $d=3$).
Based on 2005.02885, 2101.10847 and 2111.03640

### Primary authors

Dr Adrien Florio (Stony Brook University) Dr Alexander Soloviev (Stony Brook University) Prof. Derek Teaney (Stony Brook University) Dr Eduardo Grossi (IPhT Saclay) Mr Fanglida Yan (Stony Brook University)