Measurement of exclusive π+π− and ρ0 meson photoproduction at HERA
Exclusive photoproduction of ρ0(770) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction γp→π+π−Y. Reactions where the proton stays intact (mY=mp) are statistically separa...
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| Hauptverfasser: | , , , , |
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| Körperschaft: | |
| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
23 December 2020
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| In: |
The European physical journal. C, Particles and fields
Year: 2020, Jahrgang: 80, Heft: 12 |
| ISSN: | 1434-6052 |
| DOI: | 10.1140/epjc/s10052-020-08587-3 |
| Online-Zugang: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1140/epjc/s10052-020-08587-3
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| Verfasserangaben: | H1 Collaboration, V. Andreev, A. Bolz, F. Huber, M. Sauter, A. Schöning [und 133 weitere] |
| Zusammenfassung: | Exclusive photoproduction of ρ0(770) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction γp→π+π−Y. Reactions where the proton stays intact (mY=mp) are statistically separated from those where the proton dissociates to a low-mass hadronic system (mp<mY<10 GeV). The double-differential cross sections are measured as a function of the invariant mass mππ of the decay pions and the squared 4-momentum transfer t at the proton vertex. The measurements are presented in various bins of the photon–proton collision energy Wγp. The phase space restrictions are 0.5≤mππ≤2.2 GeV, |t|≤1.5 GeV2, and 20≤Wγp≤80 GeV. Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the mππ dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the ρ0(770) meson mass and width at mρ=770.8+2.6−2.7 (tot.) MeV and Γρ=151.3+2.7−3.6 (tot.) MeV, respectively. The model is used to extract the ρ0(770) contribution to the π+π− cross sections and measure it as a function of t and Wγp. In a Regge asymptotic limit in which one Regge trajectory α(t) dominates, the intercept α(t=0)=1.0654 +0.0098−0.0067 (tot.) and the slope α′(t=0)=0.233+0.067−0.074 (tot.) GeV−2 of the t dependence are extracted for the case mY=mp. |
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| Beschreibung: | Im Titel ist "+", "-" und "0" hochgestellt Gesehen am 18.02.2021 |
| Beschreibung: | Online Resource |
| ISSN: | 1434-6052 |
| DOI: | 10.1140/epjc/s10052-020-08587-3 |