Phi meson production in near threshold proton-nucleus collisions

The cross section for production of phi mesons inproton-nucleus reactions is calculatedas a function of the target mass. The decay width of the phi meson is affected by the change of the masses of the phi, K+ and K- mesons in the medium. A strong attractive K- potential leads to a measurable change of the behavior of the cross section as a function of the target mass. Comparison between the kaon and electron decay modes are made.