Kaon Condensation in ``Nuclear Star" Matter

Abstract

The critical density for kaon condensation in ``nuclear star&#34; matter is computed up to two-loop order {\it in medium} (corresponding to next-to-next-to-leading order in chiral perturbation theory in free space) with a heavy-baryon effective chiral Lagrangian whose parameters are determined from $KN$ scattering and kaonic atom data. To the order considered, the kaon self-energy has highly non-linear density dependence in dense matter. We find that the four-Fermi interaction terms in the chiral Lagrangian play an important role in triggering condensation, predicting for ``natural&#34; values of the four-Fermi interactions a rather low critical density, $ρ_c < 4 ρ_0$.