Role of the effective nucleon mass for pion condensation in nuclear matter

The dependence of the threshold for pion condensation in symmetric nuclear matter on the effective nucleon mass M^* is investigated, using extrapolations of M^*(ρ{variant}) to high densities ρ{variant}, based on boson exchange mechanisms. It is found that if M^*(ρ{variant}) decreases below the standard value M^*=0.8M as the density increases beyond the nuclear matter density ρ{variant}₀, the critical density is raised considerably beyond ρ{variant}₀ once short-range repulsive correlations are included.