Abstract:
Proton-π0 coincidences have been measured at the beam energy of 180A MeV in the reaction Ar+Ca studied by TAPS at SIS/GSI. In the proton-π0 invariant mass spectrum we observe a significant excess of strength above the background obtained by event mixing. We attribute this signal to the strength distribution N Δ of the Δ baryonic resonance. No correlation is observed in the case of deuteron-π0 coincidences. Assuming isotropic emission of π0 and Δ+ from a midrapidity thermal source and isospin symmetry, we determined the global N Δ/N πratio of 0.79 ±0.30(stat) ±0.2(syst). This value indicates that most pions produced at subthreshold energy in heavy-ion reaction are mediated by the Δ-resonance.
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Received: 7 April 2000 / Accepted: 29 August 2000
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Matulewicz, T., Aphecetche, L., Charbonnier, Y. et al. Observation of Δ+→ pπ0 decay in heavy-ion collisions. Eur Phys J A 9, 69–72 (2000). https://doi.org/10.1007/s100500070057
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DOI: https://doi.org/10.1007/s100500070057