Medium effects on ϕ meson production in near threshold proton-nucleus collisions

We study the cross section of ϕ meson production in proton-nucleus collisions. The decay width of the ϕ meson is affected by the change of the masses of the ϕ, K+ and K− mesons in the medium. A strong attractive K− potential leads to a broadening of the ϕ meson, which results in a measurable change of the behavior of the cross section as a function of the target mass.