Perspectives of $e^+e^-$ production in pp, pd and p Be reactions at SIS energies

Abstract

We study dilepton production from pp, pd and p Be collisions from 1 - 5 GeV including the $π^0$, $η$, $ω$ and $Δ$ Dalitz decays, direct decays of vector mesons ($ρ$, $ω$) as well as subthreshold $ρ$ production via baryonic resonances (e.g. $D_{13}(1520), P_{11}(1710)$). Our calculations compare rather well with the pp and pd data from the DLS Collaboration, however, overestimate slightly the 'old' p Be data from that group. Futhermore, detailed predictions for differential dilepton spectra at SIS energies are made with a high mass resolution that can be controlled experimentally by the HADES Collaboration in near future.