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HK: Physik der Hadronen und Kerne
HK 22: Elektromagnetische und hadronische Proben IV
HK 22.2: Vortrag
Dienstag, 20. März 2001, 17:00–17:15, C
Structure in the invariant mass spectrum of the ppπ− system produced in eA interactions at 5 GeV — •E. Doroshkevich1,2, G. Leksin2, M. Schepkin2, and L. Vorobyev2 — 1Physikalisches Institut der Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen — 2Institute for Theoretical and Experimental Physics, 117258, B.Cheremushkinskaya 25, Moscow, Russia
Interactions of the 5 GeV beam with the residual gas (mainly H2O) in the vacuum beam-pipe has been measured as a by-product with the large acceptance magnetic spectrometer ARGUS [1] at the e+e− storage ring DORIS II at DESY. The analysis of these data results in a mass spectrum of the ppπ− system, which exhibits a narrow resonance-like structure at Mppπ− ≈ 2.06 ÷ 2.07 GeV. To selectively look for a possible structure in the ppπ− system, we investigate the Mppπ− distribution with additional constraints, e.g. with conditions Mpp < 2mp + Δ M where Δ M = 20 MeV and Δ M = 10 MeV. The peak position coincides with the mass of the so far hypothetical d′ resonance deduced in refs. [2,3,4]. Study of the Mpπ− spectrum allows to estimate the admixture of the pΛ pairs into considered ppπ− events.
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[4] W. Brodowski et al. Z.Phys., A355 (1996) 5