φ meson mass and decay width in nuclear matter

Abstract

The \ensuremath{\varphi} meson spectrum, which in vacuum is dominated by its coupling to the $\overline{K}K$ system, is modified in nuclear matter. Following a model based on chiral SU(3) dynamics we calculate the \ensuremath{\varphi} meson self-energy in nuclear matter considering the K and $\overline{K}$ in-medium properties. For the latter we use the results of previous calculations which account for S- and P-wave kaon-nucleon interactions based on the lowest order meson-baryon chiral effective Lagrangian, and this leads to a dressing of the kaon propagators in the medium. In addition, a set of vertex corrections is evaluated to fulfill gauge invariance, which involves contact couplings of the \ensuremath{\varphi} meson to S-wave and P-wave kaon-baryon vertices. Within this scheme the mass shift and decay width of the \ensuremath{\varphi} meson in nuclear matter are studied.