A Study of Power Suppressed Contributions in $J/\psi \to p\bar{p}$ Decay

Abstract

The power suppressed amplitude which describes the Pauli (${\sigma }^{\mu \nu }$) coupling in the $J/\psi \to p\bar{p}$ decay is calculated within the effective field theory framework. It is shown that at the leading-order approximation this contribution is factorisable and the overlap with the hadronic final state can be described by collinear matrix elements. The obtained contribution depends on the nucleon light-cone distribution amplitudes of twist-3 and twist-4. This result is used for a qualitative phenomenological analysis of existing data for $J/\psi \to p\bar{p}$ decay: branching ratio and the angular distribution in the cross section $e^{+}{e}^{-}\to J/\psi \to p\bar{p}$.

Comments: Small errors and few typos are fixed, the conclusions were not changed