φ meson mass and decay width in nuclear matter

The φ meson spectrum, which in vacuum is dominated by its coupling to the K-barK system, is modified in nuclear matter. Following a model based on chiral SU(3) dynamics we calculate the φ meson self-energy in nuclear matter considering the K and K-bar 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 φ meson to S-wave and P-wave kaon-baryon vertices. Within this scheme the mass shift and decay width of the φ meson in nuclear matter are studied