Speaker
Description
Based on the epsilon expansion of the renormalization group flows of the Ginzburg-Landau potential for the chiral phase transition of QCD, it has been widely accepted that it is of first order in the zero quark mass limit for N_f > 2, with the possibility of a second order transition for N_f = 2, given the axial anomaly remains strong enough at the critical point. Going beyond the perturbative approach, I reanalyze the renormalization group flows of the Ginzburg-Landau potential using the functional renormalization group technique. Instead of employing the epsilon expansion around d = 4, with the inclusion of all (perturbatively) relevant and marginal interactions directly in d = 3, the method predicts that there exist new fixed points in the whole flavor number range potentially belonging to conformal systems going through a finite-temperature chiral transition. The results indicate that the chiral transition can be of second order for N_f >= 5, while its nature depends on the strength of the U_A(1) anomaly for N_f = 2,3,4.
