Measurement of exclusive π+π− and ρ0 meson photoproduction at HERA

• Verfasst von: Andreev, Vladimir [VerfasserIn]
• Verfasst von: Bolz, Arthur [VerfasserIn]
• Verfasst von: Huber, Florian [VerfasserIn]
• Verfasst von: Sauter, Michel David [VerfasserIn]
• Verfasst von: Schöning, André [VerfasserIn]
• Titel: Measurement of exclusive π+π− and ρ0 meson photoproduction at HERA
• Körperschaft: H1 Collaboration [VerfasserIn]
• Verf.angabe: H1 Collaboration, V. Andreev, A. Bolz, F. Huber, M. Sauter, A. Schöning [und 133 weitere]
• E-Jahr: 2020
• Jahr: 23 December 2020
• Umfang: 54 S.
• Fussnoten: Im Titel ist "+", "-" und "0" hochgestellt ; Gesehen am 18.02.2021
• Titel Quelle: Enthalten in: The European physical journal / C
• Ort Quelle: Berlin : Springer, 1998
• Jahr Quelle: 2020
• Band/Heft Quelle: 80(2020,12) Artikel-Nummer 1189, 54 Seiten
• ISSN Quelle: 1434-6052
• DOI: doi:10.1140/epjc/s10052-020-08587-3
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1748627643

Abstract

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.