Regge approach to the reaction of $\gamma N \to K^* \Lambda$

Abstract

Photoproduction of $K^*$ vector mesons off nucleon is investigated within the Regge framework where the electromagnetic vertex of $\gamma K^*K^*$ fully takes into account the magnetic dipole and electric quadrupole moments of spin-1 $K^*$ vector meson. The $t$-channel $K^*(892)$, $K(494)$ and $\kappa(800)$ meson exchanges are considered for the analysis of the production mechanism. The experimentally observed rapid decrease of the cross sections for the $\gamma p \to K^{*+} \Lambda$ reaction beyond the resonance region is well reproduced by the dominance of the exchange of $K$-meson trajectory. The role of the scalar $\kappa$-meson trajectory is found to be minor in both $\gamma p$ and $\gamma n$ reactions. The cross sections for the $\gamma n \to K^{*0} \Lambda$ reaction are predicted to be about twice those of the $\gamma p \to K^{*+}\Lambda$ reaction. The role of the $K^*$ electromagnetic multipoles and the proton anomalous magnetic moment is studied through the total and differential cross sections and spin/parity asymmetries. We suggest the measurement of the photon polarization asymmetry as a tool for identifying the role of the magnetic dipole and electric quadrupole moments of the $K^*$ vector meson.