Narrow Results

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 $\sqrt{s_{\mathrm{\text{NN}}}}=200$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.

Based on the hard-thermal-loop resummed improved ladder Dyson-Schwinger equation for the fermion mass function, we study how we can get the gauge invariant solution in the sense it satisfies the Ward identity. Properties of the "gauge-invariant" solutions are discussed.

We calculate the decay rate of the lightest heavy Majorana neutrino in a thermal bath using finite temperature cutting rules and effective Green's functions according to the hard thermal loop resummation technique. Compared to the usual approach where thermal masses are inserted into the kinematics of final states, we find that deviations arise through two different leptonic dispersion relations. The decay rate differs from the usual approach by more than one order of magnitude in the temperature range which is interesting for the weak washout regime. This work summarizes the results of Ref. 1, to which we refer the interested reader.