phi meson mass and decay width in nuclear matter

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