Nuclear Physics B (Aug 2016)

Measurement of the cross-section ratio σψ(2S)/σJ/ψ(1S) in deep inelastic exclusive ep scattering at HERA

  • H. Abramowicz,
  • I. Abt,
  • L. Adamczyk,
  • M. Adamus,
  • S. Antonelli,
  • V. Aushev,
  • Y. Aushev,
  • O. Behnke,
  • U. Behrens,
  • A. Bertolin,
  • I. Bloch,
  • E.G. Boos,
  • K. Borras,
  • I. Brock,
  • N.H. Brook,
  • R. Brugnera,
  • A. Bruni,
  • P.J. Bussey,
  • A. Caldwell,
  • M. Capua,
  • C.D. Catterall,
  • J. Chwastowski,
  • J. Ciborowski,
  • R. Ciesielski,
  • A.M. Cooper-Sarkar,
  • M. Corradi,
  • F. Corriveau,
  • R.K. Dementiev,
  • R.C.E. Devenish,
  • G. Dolinska,
  • S. Dusini,
  • J. Figiel,
  • B. Foster,
  • G. Gach,
  • E. Gallo,
  • A. Garfagnini,
  • A. Geiser,
  • A. Gizhko,
  • L.K. Gladilin,
  • Yu.A. Golubkov,
  • J. Grebenyuk,
  • I. Gregor,
  • G. Grzelak,
  • O. Gueta,
  • M. Guzik,
  • W. Hain,
  • D. Hochman,
  • R. Hori,
  • Z.A. Ibrahim,
  • Y. Iga,
  • M. Ishitsuka,
  • A. Iudin,
  • F. Januschek,
  • N.Z. Jomhari,
  • I. Kadenko,
  • S. Kananov,
  • U. Karshon,
  • M. Kaur,
  • P. Kaur,
  • D. Kisielewska,
  • R. Klanner,
  • U. Klein,
  • N. Kondrashova,
  • O. Kononenko,
  • Ie. Korol,
  • I.A. Korzhavina,
  • A. Kotański,
  • U. Kötz,
  • N. Kovalchuk,
  • H. Kowalski,
  • B. Krupa,
  • O. Kuprash,
  • M. Kuze,
  • B.B. Levchenko,
  • A. Levy,
  • V. Libov,
  • S. Limentani,
  • M. Lisovyi,
  • E. Lobodzinska,
  • B. Löhr,
  • E. Lohrmann,
  • A. Longhin,
  • D. Lontkovskyi,
  • O.Yu. Lukina,
  • I. Makarenko,
  • J. Malka,
  • S. Mergelmeyer,
  • F. Mohamad Idris,
  • N. Mohammad Nasir,
  • V. Myronenko,
  • K. Nagano,
  • T. Nobe,
  • D. Notz,
  • R.J. Nowak,
  • Yu. Onishchuk,
  • E. Paul,
  • W. Perlański,
  • N.S. Pokrovskiy,
  • M. Przybycień,
  • P. Roloff,
  • I. Rubinsky,
  • M. Ruspa,
  • D.H. Saxon,
  • M. Schioppa,
  • W.B. Schmidke,
  • U. Schneekloth,
  • T. Schörner-Sadenius,
  • L.M. Shcheglova,
  • R. Shevchenko,
  • O. Shkola,
  • Yu. Shyrma,
  • I. Singh,
  • I.O. Skillicorn,
  • W. Słomiński,
  • A. Solano,
  • L. Stanco,
  • N. Stefaniuk,
  • A. Stern,
  • P. Stopa,
  • J. Sztuk-Dambietz,
  • D. Szuba,
  • J. Szuba,
  • E. Tassi,
  • K. Tokushuku,
  • J. Tomaszewska,
  • A. Trofymov,
  • T. Tsurugai,
  • M. Turcato,
  • O. Turkot,
  • T. Tymieniecka,
  • A. Verbytskyi,
  • O. Viazlo,
  • R. Walczak,
  • W.A.T. Wan Abdullah,
  • K. Wichmann,
  • M. Wing,
  • G. Wolf,
  • S. Yamada,
  • Y. Yamazaki,
  • N. Zakharchuk,
  • A.F. Żarnecki,
  • L. Zawiejski,
  • O. Zenaiev,
  • B.O. Zhautykov,
  • N. Zhmak,
  • D.S. Zotkin

DOI
https://doi.org/10.1016/j.nuclphysb.2016.06.010
Journal volume & issue
Vol. 909, no. C
pp. 934 – 953

Abstract

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The exclusive deep inelastic electroproduction of ψ(2S) and J/ψ(1S) at an ep centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range 2<Q2<80 GeV2, 30<W<210 GeV and |t|<1 GeV2, where Q2 is the photon virtuality, W is the photon–proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The data for 2<Q2<5 GeV2 were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb−1. The data for 5<Q2<80 GeV2 are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb−1. The decay modes analysed were μ+μ− and J/ψ(1S)π+π− for the ψ(2S) and μ+μ− for the J/ψ(1S). The cross-section ratio σψ(2S)/σJ/ψ(1S) has been measured as a function of Q2,W and t. The results are compared to predictions of QCD-inspired models of exclusive vector-meson production.