CHARGED PION-CONDENSATION IN THE CHIRAL LIMIT

We examine, in the chiral limit where the up and down quark masses are vanishingly small, the stability of the pure neutron ground state to small fluctuations due to charge and baryon number conserving strong interactions. It is shown that the ground state energy density as a function of pion field expectation value is determined by Weinberg's baryon two-body potential and by a calculable neutron-proton mass difference in the medium. This provides some insight into the competing physical effects that play a role in determining whether a charged pion condensate forms in dense nuclear matter. We find that in the chiral limit these effects suppress charged pion condensation.