The cross sections for the charmonium production processes pp → mΨ, where m is a light meson and Ψ is a charmonium state, are of great interest for the planned pp experiment PANDA. In this paper we estimate these cross sections using known results for the decays Ψ → mpp, 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 pp → π 0 J/ψ, which was reported by E760 to be 130 ± 25 pb near √ 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 Ψ → mpp Dalitz plots.

Recent lattice-QCD calculations of the charmonium hybrid spectrum predict the ground state hybrid to be a spin-exotic with quantum number J PC 1 · at a mass of about 4.3 GeV c 2 .Such a low mass hybrid could be as narrow as O´20MeV c 2 µ due to dynamical suppression of decay into open charm. The exotic quantum numbers prevent the state from mixing with conventional mesons and simplifies the identification of the state as a non-meson state. Lattice calculations name the most obvious hybrid charmonium decay channel to be a conventional charmonium and light hadrons. The detection of such a final state with seven photons and a lepton pair within the future PANDA detector at GSI is investigated with Monte Carlo methods at Uppsala University.