Dilepton production from virtual bremsstrahlung induced by proton capture

Dilepton production following radiative capture of a proton on a nuclear target is studied in the impulse approximation. The cross section is decomposed in terms of four time-like nuclear structure functions through a longitudinal-transverse separation of the nuclear current. Using a simple PWIA model, cross sections and conversion factors are calculated for capture reactions p+n→d+e+e-, p+p→2He+e+e- and p+11B→12C+e+e- at proton energies of 100-200 MeV. The result is compared with a recent measurement of the conversion factor for p+11B. ((orig.))