Strangeness Equilibration at Gsi Energies

We develop the notion of " broad-band equilibration " in heavy-ion processes involving dense medium. Given density-dependent K −-masses we show that the equilibration at GSI energies claimed to hold in previous treatments down to ∼ ρ 0 /4, can be replaced by a broad-band equilibration in which the K −-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 both K + and K − must get lighter in dense medium at some density ρ > ρ 0 due to the decoupling of the vector mesons. As a consequence, kaon condensation in compact stars could take place before chiral restoration since the sum of bare quark masses in the kaon should lie below µ 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.