Covariant tensor formalism for partial wave analyses of $\psi$ decays into $\gamma B\bar B$

Abstract

Recently BES2 collaboration observed an enhancement near the $p\bar p$ invariant mass spectrum. Using the covariant tensor formalism, here we provide theoretical formulae for the partial wave analysis (PWA) of the $\psi$ radiative decay channels $\psi \to \gamma p\bar p, \gamma\Lambda\bar \Lambda, \gamma\Sigma \bar\Sigma, \gamma\Xi\bar \Xi$ . By performing the Monte Carlo simulation, we give the angular distributions for the photon and proton in the process of $J/\psi \to \gamma p\bar p$, which may serve as a useful reference for the future PWA on these channels.