In this paper we report on the investigation of baryonic resonance production in proton-proton collisions at kinetic energy 1.25 GeV measured with HADES. Exclusive channels ppe+e- and ppe+e-γ as well as ppπ0 and npπ+ were studied. The resonance cross section was determined from hadronic channels in the framework of a one boson exchange model with the accuracy of 15%. The dilepton analysis proved the resonance origin of e+e- pairs and the Δ Dalitz decay was identified experimentally (in the pe+e- channel) for the first time. Investigation of hadronic reaction channels by means of the Partial Wave Analysis revealed a dominant contribution of P33(1232) but also sizeable non-resonant terms and interference effects.
Baryon resonance production and dielectron decays in proton-proton collisions at 3.5 GeV