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.Comment: 15 pages, 6 figure
