Strangeness Equilibration at GSI Energies

Abstract

We develop the notion of "broad-band equilibration" in heavy-ion processes involving dense medium. Given density-dependent \Km-masses we show that the equilibration at GSI energies claimed to hold in previous treatments down to $\sim {\rho }_0/4$, can be replaced by a broad-band equilibration in which the \Km-meson and hyperons are produced in an essentially constant ratio independent of density. There are experimental indications that this also holds for AGS energies. We then proceed to argue that {\it both} $K^{+}$ and $K^{-}$ must get lighter in dense medium at some density $\rho >{\rho }_0$ due to the decoupling of the vector mesons. As a consequence, kaon condensation in compact stars could take place {\it before} chiral restoration since the sum of bare quark masses in the kaon should lie below ${\mu }_e$. Another consequence of the decoupling vector interactions is that the quasi-particle picture involving (quasi)quarks, presumably ineffective at low densities, becomes more appropriate at higher densities as chiral restoration is approached.

Comments: 16 pages, latex with 2 eps figures. Abstract rewritten and references updated