Studying hadron properties in baryonic matter with HADES

The HADES spectrometer installed at GSI Darmstadt is a second generation experiment to study production of lepton pairs from proton, pion and nucleus induced reactions at the SIS/BEVALAC energy regime. The HADES study of the light C+C system at 1 and 2 AGeV confirms former finding of the DLS collaboration. Further studies of the reaction p+p and d+p allowed to reveal contribution to the above mentioned data of di‐leptons produced during first chance collision. Finally, the results of the study of heavier system Ar+KCl indicates possible nonlinear dependence of the observed excess over the known long lived sources of di‐leptons on the number of participants.