ρ-Exchange Contribution toγn→ρ−p

Abstract

The process $\ensuremath{\gamma}n\ensuremath{\rightarrow}{\ensuremath{\rho}}^{\ensuremath{-}}p$ is studied in the framework of Born approximation for the $\ensuremath{\rho}$ exchange with two different procedures for gauge correction. The resulting differential cross section is very sensitive to the value of the magnetic moment of the $\ensuremath{\rho}$ meson, ${\ensuremath{\mu}}_{\ensuremath{\rho}}$. Comparison with the experimental results for photon energies $1.4<{E}_{\ensuremath{\gamma}}<2.5$ GeV enables us to obtain an estimate of ${\ensuremath{\mu}}_{\ensuremath{\rho}}\ensuremath{\approx}2{\ensuremath{\mu}}_{N}$, which, in the light of the necessary refinements of the crude model used here, is regarded as a lower limit. This result is consistent with theoretical predictions of ${\ensuremath{\mu}}_{\ensuremath{\rho}}$, such as in the $q\overline{q}$ quark model or the $N\overline{N}$ Fermi-Yang model. The calculated density matrix provides a tool to discern the $\ensuremath{\rho}$-exchange contribution from the rest.