FAIR next generation scientists - 8th Edition Workshop

In this contribution we present preliminary results on the dielectron production in p+p interactions at $1.58$GeV beam energy measured with the High Acceptance DiElectron Spectrometer (HADES). The HADES RICH detector has been upgraded with a new photon detection camera which strongly enhances the electron efficiency and conversion pair rejection. With this upgrade, a signal-to-background ratio above 1 is achieved over the entire dielectron spectrum. $0.5$billion collisions have been analyzed showing a contribution of ${\pi }^0$ and $\eta$ Dalitz decays in a signal up to an invariant mass of $0.5$GeV/$c^2$. Furthermore, by analyzing elastic p+p collisions, a normalization procedure for differential cross sections has been established.

The cross section spectrum shows a satisfactory agreement to previous HADES measurements as well as theoretical calculations from GiBUU. Furthermore this spectrum can serve as a baseline for the understanding and interpretation of Ag+Ag collisions which have been measured in HADES at the same energy. A precise understanding of the dielectron production in elementary reactions is needed to disentangle the various contributions to the measured dielectron yield in Ag+Ag collisions.