Photoproduction of the $\pi N$ pair on nuclei and isobar configurations

Abstract

A model of $\pi N$ pair photoproduction on nuclei at high momentum transfer is presented. The $A(\gamma ,\pi N)B$ reaction amplitude is obtained by means of an extended impulse approximation, according to which the nuclear wavefunction includes delta-isobar components in addition to nucleon components. A one-particle transition operator is defined in terms of the two-body $\gamma N\to \pi N$ and $\gamma \Delta \to \pi N$ photoproduction amplitudes. Direct and exchange mechanisms of the nuclear photoproduction reaction are studied, and numerical estimates are made and presented of ${}^{12}\mathrm{C}(\gamma ,{\pi }^{-}p){}^{11}\mathrm{C}$ and ${}^{12}\mathrm{C}(\gamma ,{\pi }^{+}p){}^{11}\mathrm{Be}$ differential cross sections at photon incident energies in the $\Delta (1232)$ resonance region.

Comments: LaTeX 2e, 21 pages, 5 eps figures