Measuring the ϕ meson width in the medium from p induced ϕ production in nuclei

We study the A dependence of the ϕ meson production cross section in proton nucleus reactions at energies just above threshold, which are accessible in an experimental facility like COSY. This A dependence has two sources: the distortion of the incident proton and the absorption of the ϕ in its way out of the nucleus. This second process reduces the cross section in about a factor two in heavy nuclei. Thus we show that the A dependence of the cross section contains valuable information on the ϕ width in the nuclear medium.