Electron-Positron Annihilation into Hadron-Antihadron Pairs
  The reactions of electron-positron to nucleon-antinucleon pairs are studied in a non-perturbative quark model. The work suggests that the two-step process, in which the primary quark-antiquark pair forms first a vector meson which in turn decays into a hadron pair, is dominant over the one-step process in which the primary quark-antiquark pair is directly dressed by additional quark-antiquark pairs to form a hadron pair. To reproduce the experimental data of the reactions of electron-positron to proton-antiproton and electron-positron to neutron-antineutron a D-wave omega-like vector meson with a mass of around 2 GeV has to be introduced. 
Y. Yan, C. Kobdaj, P. Suebka, Z.M. Zheng, Amand Faessler, Th. Gutsche,   V.E. Lyubovitskij