Hadronic production of theψJmeson

Abstract

It is proposed that the production of $\frac{\psi }{J}$ mesons in hadronic collisions occurs via processes involving gluons, and that reactions with ${}_{}{}^3{}_{}{}^{}P$ charmonium intermediate states play a significant role. The clarity of the observed $\frac{\psi }{J}$ signal and the differences between production rates of $\frac{\psi }{J}$ in pion- and nucleon-induced reactions are explained naturally. We calculate the total and differential cross section for producing $\frac{\psi }{J}+\mathrm{anything}$, and compare to data. Also, we have calculated the decay rates of the ${}_{}{}^3{}_{}{}^{}P$ states into two gluons; these results may be interesting in their own right.