Experiments with Pion-Beam

The HADES Pion Beam Facility

Nuclear Physics News ◽

10.1080/10619127.2015.1035929 ◽

2015 ◽

Vol 25 (2) ◽

pp. 22-24 ◽

Cited By ~ 3

Author(s):

Piotr Salabura ◽

Joachim Stroth ◽

Laura Fabbietti

Keyword(s):

Pion Beam

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Measurement of punch-through particle fluxes from a 200 cm long beam dump hit by a 300 GeV/c pion beam

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/0168-9002(86)90673-x ◽

1986 ◽

Vol 249 (2-3) ◽

pp. 251-256 ◽

Cited By ~ 1

Author(s):

J. Badier ◽

C. Bemporad ◽

J. Boucrot ◽

O. Callot ◽

Ph. Charpentier ◽

...

Keyword(s):

Pion Beam ◽

Beam Dump ◽

Particle Fluxes

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Studying time-like electromagnetic baryonic transitions with HADES in pion induced reactions

EPJ Web of Conferences ◽

10.1051/epjconf/202024101012 ◽

2020 ◽

Vol 241 ◽

pp. 01012

Author(s):

Béatrice Ramstein

Keyword(s):

Center Of Mass ◽

Quantitative Description ◽

Form Factors ◽

Resonance Region ◽

Partial Wave Analysis ◽

Real Photon ◽

Pion Beam ◽

Dalitz Decay ◽

Covariant Model ◽

Proton Induced Reactions

A dedicated programme aiming at studying electromagnetic baryonic transitions in the time-like region has started at GSI using the pion beam and the High Acceptance Di-Electron Spectrometer (HADES) set-up. A pioneering experiment has been carried out in the second resonance region, at a center-of-mass energy of 1.49 GeV, using carbon and polyethylene targets, allowing for an analysis of the inclusive e+e- production and of the exclusive quasi-free π-p → ne+e- reaction, in complement to hadronic channels. Predictions for the Dalitz decay of N(1520) and N(1535) based on real photon couplings strongly underestimate the e+e- yield at invariant masses larger than 300 MeV/c2, which signals effects of time-like baryon transition form factors, in qualitative agreement with the Vector Dominance Models (VDM). A quantitative description of the observed e+e- yield is achieved by taking into account the contribution from off-shell ρs. The latter was provided by the preliminary results of a Bonn-Gatchina Partial Wave Analysis of the two-pion production channels, which were measured simultaneously in our experiment. A good agreement is also obtained using a covariant model for the time-like electromagnetic form factors for the N-N(1520) transition. The angular distributions for the e+e- production contain additional selective information on the spin structure of the different transitions. The measurements with the pion beam will be extended in future in the third resonance region. Hyperon Dalitz decay studies in proton induced reactions are also foreseen.

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