Exclusive decay of $J/\Psi$ into a lepton pair combined with light hadrons

Abstract

We study the exclusive decay of $J/\Psi$ into a lepton pair combined with light hadrons in the kinematic region, specified by that the total energy of the light hadrons is much smaller than $m_c$, the mass of the $c$-quark. In this region, the nonperturbaive effect related to $J/\Psi$ and that related to the light hadrons can be separated, the former is represented by a NRQCD matrix element, while the later is represented by a matrix element of a correlator of electric chromofields. The results are obtained in a axial gauge by assumming that contributions from two-gluon emmssion are dominant. But we can show that these results can be obtained without the assumption in arbitrary gauges. A discussion of the results are presented.