DILEPTON PRODUCTION FROM VIRTUAL BREMSSTRAHLUNG INDUCED BY PROTON CAPTURE

Dilepton production following radiative capture of a proton on a nucle ar target is studied in the impulse approximation. The cross section i s decomposed in terms of four time-like nuclear structure functions th rough a longitudinal-transverse separation of the nuclear current. Usi ng a simple PWIA model, cross sections and conversion factors are calc ulated for capture reactions p+n-->d+e+e-, p+p-->He-2+e+e- and p+B-11- ->C-12+e+e- at proton energies of 100-200 MeV. The result is compared with a recent measurement of the conversion factor for p+B-11.