Charmonium production in p pbar annihilation: Estimating cross sections from decay widths

Abstract

The cross sections for the charmonium production processes p pbar -> m Psi, where m is a light meson and Psi is a charmonium state, are of great interest for the planned p-pbar experiment PANDA. In this paper we estimate these cross sections using known results for the decays Psi -> m p pbar which are related to these reactions by crossing. In lieu of detailed experimental data on the decay Dalitz plots, we assume a constant amplitude as a first approximation; this implies a simple relation between the cross sections and decay widths. The single measured exclusive cross section of this type is p pbar -> pi0 J/psi, which was reported by E760 to be 130 +/- 25 pb near sqrt(s) = 3.5-3.6 GeV. In comparison, our constant amplitude estimate is about 300 pb at this energy. This suggests that our approach is useful as a simple estimate, but should be refined through detailed modeling of resonances and other energy-dependent effects in the experimental Psi -> m p pbar Dalitz plots.