The φ meson width in the medium from proton induced φ production in nuclei March 3 , 2008

We perform calculations for the production of φ mesons in nuclei at energies just above threshold and study the A dependence of the cross section. We use results for the φ selfenergy in the medium obtained within a chiral unitary approach. We find a strong A dependence which is tied to the distortion of the incident proton and to the absorption of the φ in its way out of the nucleus. The effect of this latter process reduces the cross section in about a factor two in heavy nuclei proving that the A dependence of the cross section bears valuable information on the φ width in the nuclear medium. Calculations are done for energies which are accessible in an experimental facility like COSY.