Strange meson production at high density and temperature

The properties of strange mesons ($K$, $\bar{K}$ and ${\bar{K}}^{\ast }$) in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. The kaon-nucleon interaction incorporates $s$- and $p$-wave contributions within a chiral model whereas the interaction of $\bar K^*$ with nucleons is obtained in the framework of the local hidden gauge formalism. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects, mean-field binding on baryons, and meson self-energies. We obtain the $K$, $\bar{K}$ and ${\bar{K}}^{\ast }$ (off-shell) spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also analyze the energy weighted sum rules of the kaon propagator as a quality test of model calculations. We finally estimate the transparency ratio of the $\gamma A\to K^{+}{K}^{\ast -}{A}^{\mathrm{\prime }}$ reaction, which we propose as a feasible scenario at present facilities to detect in-medium modifications of the ${\bar{K}}^{\ast }$ meson.