Quantum chromodynamics with various number of flavors

TL;DR

This study investigates the phase structure of QCD with different numbers of flavors using Wilson quarks, revealing how the order of phase transitions varies with flavor number and comparing SU(2) and SU(3) cases.

Contribution

It provides new insights into the flavor dependence of the QCD phase transition order and the critical flavor number where confinement breaks down in strong coupling.

Findings

Finite temperature deconfining transition is first order for N_F=3 on an N_t=4 lattice.

Transition order varies with N_F, consistent with universality predictions.

Confinement is broken at strong coupling for N_F ≥ N_F^* in SU(2) QCD, similar to SU(3).

Abstract

The phase structure of QCD with various number of flavors is studied for Wilson quarks. For the case of $N_F=3$ we find that the finite temperature deconfining transition is of first order in the chiral limit on an $N_t=4$ lattice. Together with our previous results that the deconfining transition in the chiral limit is continuous for $N_F=2$ and is first order for $N_F=6$, the order of the transition is found to be consistent with a prediction of universality. The case of $SU(2)$ QCD is also studied in the strong coupling limit and the phase structure is found to be quite similar to the case of $SU(3)$: There exists a critical number of flavors $N_F^*$ and for $N_F \geq N_F^*$ the confinement is broken even in the strong coupling limit for light quarks. $N_F^*=3$ corresponding to 7 for $SU(3)$.