Münster 2017 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 57: Hadron Structure and Spectroscopy VII
HK 57.7: Vortrag
Freitag, 31. März 2017, 16:00–16:15, F 5
Baryon electromagnetic transitions in pion induced reactions with HADES — •Federico Scozzi for the HADES collaboration — TU Darmstadt, Germany — IPN Orsay, France
Several experiments showed an enhancement in di-lepton invariant mass spectra below the vector meson pole both in proton-nucleus and in nucleus-nucleus collisions. The main interpretation of this effect is based on the strong coupling of the ρ meson to the baryonic resonances. In summer 2014 data were taken with the High Acceptance Di-Electron Spectrometer (HADES) at GSI in pion-induced reactions with the aim to study the coupling of the ρ with the baryonic resonances in the second resonance region by means of the reactions π−p → π+ π− n and π−p → π0 π− p. In addition, the role of the ρ meson in electromagnetic transitions in the time-like region is investigated in the reaction π−p → e+ e− n. In this contribution results of dilepton invariant mass spectra will be presented in comparison with different models. In addition, the connection with the two-pion production channels allows to investigate the validity of the Vector Dominance Model. Finally the angular distributions of the leptons, which contain additional information on the electromagnetic properties of the different contributions, will be discussed.
This work has been supported by VH-NG-823, Helmholtz Alliance HA216/EMMI and GSI.