학술논문
Measurement of the cross-section ratio σ ψ(2S) /σ J/ψ(1S) in exclusive photoproduction at HERA
Document Type
article
Author
The ZEUS collaboration; I. Abt; M. Adamus; R. Aggarwal; V. Aushev; O. Behnke; A. Bertolin; I. Bloch; I. Brock; N. H. Brook; R. Brugnera; A. Bruni; P. J. Bussey; A. Caldwell; C. D. Catterall; J. Chwastowski; J. Ciborowski; R. Ciesielski; A. M. Cooper-Sarkar; M. Corradi; R. K. Dementiev; S. Dusini; J. Ferrando; B. Foster; E. Gallo; D. Gangadharan; A. Garfagnini; A. Geiser; G. Grzelak; C. Gwenlan; D. Hochman; N. Z. Jomhari; I. Kadenko; U. Karshon; P. Kaur; R. Klanner; U. Klein; I. A. Korzhavina; N. Kovalchuk; M. Kuze; B. B. Levchenko; A. Levy; B. Löhr; E. Lohrmann; A. Longhin; F. Lorkowski; I. Makarenko; J. Malka; S. Masciocchi; K. Nagano; J. D. Nam; Yu. Onishchuk; E. Paul; I. Pidhurskyi; A. Polini; M. Przybycień; A. Quintero; I. Rubinsky; M. Ruspa; U. Schneekloth; T. Schörner-Sadenius; I. Selyuzhenkov; M. Shchedrolosiev; L. M. Shcheglova; I. O. Skillicorn; W. Słomiński; A. Solano; L. Stanco; N. Stefaniuk; B. Surrow; K. Tokushuku; J. Tomaszewska; A. Trofymov; O. Turkot; T. Tymieniecka; A. Verbytskyi; W. A. T. Wan Abdullah; K. Wichmann; M. Wing; S. Yamada; Y. Yamazaki; A. F. Żarnecki; O. Zenaiev
Source
Journal of High Energy Physics, Vol 2022, Iss 12, Pp 1-27 (2022)
Subject
Language
English
ISSN
1029-8479
Abstract
Abstract The exclusive photoproduction reactions γp → J/ψ(1S)p and γp → ψ(2S)p have been measured at an ep centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb −1. The measurement was made in the kinematic range 30 < W < 180 GeV, Q 2 < 1 GeV2 and |t| < 1 GeV2, where W is the photon-proton centre-of-mass energy, Q 2 is the photon virtuality and t is the squared four-momentum transfer at the proton vertex. The decay channels used were J/ψ(1S) → μ + μ − , ψ(2S) → μ + μ − and ψ(2S) → J/ψ(1S)π + π − with subsequent decay J/ψ(1S) → μ + μ − . The ratio of the production cross sections, R = σ ψ(2S) /σ J/ψ(1S), has been measured as a function of W and |t| and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production, which are in reasonable agreement with the data.