The $ϕ$ meson width in the medium from proton induced $ϕ$ production in nuclei

Abstract

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.

26 pages, 13 figures. More detailed calculations have been performed. Paper is accepted for publication in Phys. Rev. C