T–μ phase diagram of the chiral quark model from a large flavor number expansion

Abstract The chiral phase boundary of strong matter is determined in the T – μ plane from the chiral quark model, applying a non-perturbatively renormalised treatment, involving chains of pion-bubbles and 1-loop fermion contributions. In the absence of explicit symmetry breaking the second order portion of the phase boundary and the location of the tricritical point (TCP) are determined analytically. Sensitivity of the results to the renormalisation scale is carefully investigated. The softening of the σ -pole near the second order transitions is confirmed.