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Phi meson mass and decay width in nuclear matter

The $ϕ$ meson spectrum, which in vacuum is dominated by its coupling to the $\bar{K} K$ system, is modified in nuclear matter. Following a model based on chiral SU(3) dynamics we calculate the $ϕ$ meson selfenergy in nuclear matter considering the $K$ and $\bar{K}$ 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 $ϕ$ 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.