Direct Photon Production in High-Energy Heavy Ion Collisions within the Integrated Hydrokinetic Model

The results on description of direct photon yields, transverse momentum spectra, and flow harmonics, measured in ultrarelativistic heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) for different collision centrality classes, analyzed within the Integrated Hydrokinetic Model (iHKM) are reviewed. The iHKM simulation results, corresponding to the two opposite approaches to the matter evolution treatment at the final stage of the system’s expansion within the model, namely, the chemically equilibrated and the chemically frozen evolution, are compared. The so-called “direct photon puzzle” is addressed, and its possible solution, suggesting the account for additional photon emission at confinement, is considered.

Quantized vortices in pionic superfluid

The interplay between classical vorticity being the main undisputed source of polarization in heavy-ion collisions (HIC) and quantized vortices is considered. The vortex tubes emerging in the rotating pionic (super) fluid polarize the baryons in their cores and explain the emerging global polarization. The appearance of vortices in the region separating participants and spectators in non-central HIC is similar to that for sliding layers of liquid helium. From the other side, it is also the region where the classical vorticity was earlier found to be large forming the vortex sheets. The formation of tubes manifests a threshold at certain critical vorticity implying the vanishing polarization at lower energies. For central HIC the compact jet-like flows may lead to formation of vortex rings related to local polarization. The P-odd momentum correlations for their experimental investigation are suggested. The role of shear and viscosity in the emergence of polarization is discussed.

Far from equilibrium Chiral Magnetic Effect in Strong Magnetic Fields from Holography

We study the real time evolution of the chiral magnetic effect out-ofequilibrium in strongly coupled anomalous field theories. We match the parameters of our model to QCD parameters and draw lessons of possible relevance for the realization of the chiral magnetic effect in heavy ion collisions. In particular, we find an equilibration time of about ~ 0:35 fm/c in presence of the chiral anomaly for plasma temperatures of order T ~ 300 - 400 MeV.