Dilepton production in proton+nucleon collisions

The author calculates dielectron production from proton-proton and proton-neutron reactions for energies above hadronic inelastic thresholds. Simple bremsstrahlung from proton-proton scattering is not small compared with proton-neutron at these energies. This shows a clear breakdown of the dipole approximation. The many-pion final states are shown to radiate even more strongly than simple bremsstrahlung. The author adds the total bremsstrahlung contribution to Dalitz decay of the η, radiative decay of the Δ and to two-pion annihilation and compares with proton-proton inclusive cross sections and ratios of pd/pp yields from the Dilepton Spectrometer