π+π−emission from coherentρ0propagation in nuclei

Abstract

Cross sections for the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ events arising from the decay of the ${\ensuremath{\rho}}^{0}$ meson have been calculated. This \ensuremath{\rho} meson is considered to be produced coherently in the $(p,{p}^{'})$ reaction in a nucleus. The distorted-wave functions for the continuum particles and the \ensuremath{\rho} meson propagator are described by the eikonal form. The sensitivity of the cross section to the pion emission angle as well as to the beam energy has been investigated. The cross sections for the ${\ensuremath{\rho}}^{0}$ meson decaying inside and outside the nucleus are compared. In addition, the coherent and incoherent contributions to the cross section due to ${\ensuremath{\rho}}^{0}$ inside and outside decay amplitudes are presented. The initial- and final-state interactions for this reaction have been studied. The nuclear medium effect on ${\ensuremath{\rho}}^{0}$-meson propagation through the nucleus is also explored.