Dilepton production from virtual bremsstrahlung induced by proton capture

Abstract

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 $\text{p}\text{+}\text{n}\text{→}\text{d}\text{+}\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{-}}\text{,}\text{p}\text{+}\text{p}\text{→}{}^2\text{He}\text{+}\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{-}}\text{and p}\text{+}{}^{11}\text{B}\text{→}{}^{12}\text{C}\text{+}\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{-}}$ at proton energies of 100–200 MeV. The result is compared with a recent measurement of the conversion factor for p+¹¹B.