Two-pion production in the second resonance region in π-p collisions with the High-Acceptance Di-Electron Spectrometer (HADES)

Pion-induced reactions provide unique opportunities for an unambiguous description of baryonic resonances and their coupling channels by means of a partial-wave analysis. Using the secondary pion beam at SIS18, the two-pion production in the second resonance region has been investigated to unravel the role of the N(1520)32- resonance in the intermediate ρ-meson production. Results on exclusive channels with one pion (π-p) and two pions (π+π-n, π0π-p) in the final state measured in the π - p reaction at four different pion beam momenta (0.650, 0.685, 0.733, and 0.786 GeV/c) are presented. The excitation function of the different partial waves and Δπ, Nσ, and Nρ isobar configurations is obtained, using the Bonn-Gatchina partial-wave analysis. The N(1520)32- resonance is found to dominate the Nρ final state with the branching ratio BR=12.2%±1.9%.