Viscosity to entropy ratio of QGP in relativistic heavy ion collision: Hard thermal loop corrections

In this work, we report on our computation results for the best value of the shear viscosity to entropy ratio of quark–gluon plasma produced in the relativistic Au–Au collisions at [Formula: see text][Formula: see text]GeV. Time evolution of heavy quarks distribution functions is calculated by solving the Fokker–Planck evolution equation using the new technique: Iterative Laplace transform method. We compute the drag and diffusion coefficients by considering the hard thermal loop corrections and also temperature dependence running strong coupling, up to complete interactions of leading order.

Recent progress in hard-thermal-loop QCD thermodynamics and collective excitations

I review recent developments in QCD thermodynamics and collective excitations from the hard-thermal-loop effective theory. I begin by motivating the discussion with open questions from heavy-ion collisions. I then discuss a finite-temperature and density calculation of QCD thermodynamics at NNLO from the hard-thermal-loop perturbation theory. Finally, I discuss a recent exploration of generalizing the hard-thermal-loop framework to the (chromo)magnetic scale g2T, from which a novel massless mode is uncovered.