Study of exclusive one-pion and one-eta production using hadron and dielectron channels in pp reactions at kinetic beam energies of 1.25 GeV and 2.2 GeV with HADES

Abstract

We present measurements of exclusive π^{+,0} and η production in pp reactions at 1.25 GeV and 2.2 GeV beam kinetic energy in hadron and dielectron channels. In the case of π^+ and π^0, high-statistics invariant-mass and angular distributions are obtained within the HADES acceptance as well as acceptance corrected distributions, which are compared to a resonance model. The sensitivity of the data to the yield and production angular distribution of Δ(1232) and higher lying baryon resonances is shown, and an improved parameterization is proposed. The extracted cross sections are of special interest in the case of pp \to pp η, since controversial data exist at 2.0 GeV; we find σ=0.142 \pm 0.022 mb. Using the dielectron channels, the π^0 and η Dalitz decay signals are reconstructed with yields fully consistent with the hadronic channels. The electron invariant masses and acceptance corrected helicity angle distributions are found in good agreement with model predictions.

22 pages, 18 figures, to be published in EPJA

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Cited by in corpus (15)

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• Baryon resonance production and dielectron decays in proton-proton collisions at 3.5 GeV
• Study of the quasi-free $np\to np{\pi }^{+}{\pi }^{-}$ reaction with a deuterium beam at 1.25 GeV/nucleon
• $\Delta$(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES
• Dilepton Radiation from Strongly Interacting Systems
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• The study of the proton-proton collisions at the beam momentum 1628 MeV/c
• Analysis of pion production data measured by HADES in proton-proton collisions at 1.25 GeV
• Search for an Isospin I =3 Dibaryon
• Covariant model for the Dalitz decay of the $N(1535)$ resonance
• Analysis of the exclusive final state npe${}^{+}$e${}^{-}$ in quasi-free np reaction
• Near-threshold $\eta$ production in $pp$ collisions
• Search for η-->e+e- decay with the WASA experiment