Speaker: Péter Kovács (Wigner RCP)
Title: Fate of the QCD critical endpoint at large N_c
Date: 21 October 2022, 14 p.m.
Place: Building 3 meeting room
The phase diagram of QCD is investigated by varying number of colors N_c within a Polyakov loop quark-meson chiral model. The first part of the talk is dedicated to the introduction of the basics of the large N_c technique. In the second part our attention is focused on the critical point(s). It turns out that the critical point present for N_c = 3 moves toward the µ_q-axis and disappears as soon as the number of color is increased. Yet, a distinct critical point emerges along the temperature axis for N_c = 53 and moves toward finite density when increasing N_c further. Thus, the phase diagram at large N_c looks like the opposite to the Nc = 3 results, with the first order transition in the upper-left and crossover in the down-right regions of the (µ_q,T)-plane. The pressure is also evaluated in dependence of N_c, showing a scaling with N_c^0 in the confined and chirally broken phase and with N_c^2 in the deconfined one. Moreover, the presence of a chirally symmetric but confined ‘quarkyonic phase’ at large density and moderate temperature with a pressure proportional to N_c is confirmed.