${\bar{K}}^{\ast }$ meson in dense matter

Abstract

We study the properties of ${\bar{K}}^{\ast }$ mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the $\bar{K}\ddot{I}€$ decay channel in matter. The in-medium ${\bar{K}}^{\ast }N$ interaction accounts for Pauli blocking effects and incorporates the ${\bar{K}}^{\ast }$ self-energy in a self-consistent manner. We also obtain the ${\bar{K}}^{\ast }$ (off-shell) spectral function and analyze its behaviour at finite density and momentum. At normal nuclear matter density, the ${\bar{K}}^{\ast }$ meson feels a moderately attractive potential while the ${\bar{K}}^{\ast }$ width becomes five times larger than in free space. We estimate the transparency ratio of the ${\hat{I}}^{3}A\to K^{+}{K}^{\ast -}{A}^{\prime }$ reaction, which we propose as a feasible scenario at present facilities to detect the changes of the properties of the ${\bar{K}}^{\ast }$ meson in the nuclear medium.

26 pages, 9 figures, one new section added, version published in Phys. ReV. C, http://link.aps.org/doi/10.1103/PhysRevC.82.045210