mgr Valeriya Mykhaylova

Promotor: Dr. hab. Chihiro Sasaki, Prof. UWr

Transport Properties of Hot QCD Matter in the Quasiparticle Approach

I recenzent: prof. dr hab. Stanisław Mrówczyński, Zakład Fizyki Wielkich Energii, Narodowe Centrum Badań Jądrowych

II recenzent: prof. dr hab. Wojciech Florkowski, Instytut Fizyki im. Mariana Smoluchowskiego Uniwersytetu Jagiellońskiego

III recenzent: dr hab. Radosław Ryblewski, Instytut Fizyki Jądrowej Polskiej Akademii Nauk

In this Thesis, we investigate the transport properties of hot QCD matter in the quasiparticle model. We consider quasiparticle excitations with quark and gluon quantum numbers as effective degrees of freedom in the deconfined phase. The interactions with a hot medium are embodied in dynamical masses of the constituents and temperature-dependent dispersion relations through the effective running coupling extracted from lattice QCD thermodynamics. We study the temperature and flavor dependence of different transport parameters of the deconfined matter in pure Yang-Mills theory and QCD with light and strange quark flavors. The calculations are performed in kinetic theory under the relaxation time approximation, with relaxation times that depend explicitly on the microscopic two-body scatterings of the quasiparticles. Finally, we employ the acquired shear viscosity in the investigation of charm quark production. By comparing perfect QGP propagating longitudinally with the viscous QGP also expanding in the transverse direction, we observe that the latter setup significantly induces the production of charm-anticharm pairs. However, as QGP approaches the phase transition temperature, the majority of heavy quarks annihilate in the perfect fluid. At the same time, in a viscous medium, the final number of charm-anticharm pairs in certain cases equals the initial one, which agrees with the experimental observations. We find a universal behavior of the charm quark number as a function of temperature and time at the late stage of the QGP evolution. This can be linked to the rate equation used in our calculations, which is characterized by the general property of differential equations to have a universal (attracting) solution.

The defense will be held in Aula Leopoldina, pl. Uniwersytecki 1