Photoproduction of J ψ mesons at HERA

Academic Article


  • We present a study of J ψ meson production in collisions of 26.7 GeV electrons with 820 GeV protons, performed with the H1-detector at the HERA collider at DESY. The J ψ mesons are detected via their leptonic decays both to electrons and muons. Requiring exactly two particles in the detector, a cross section of σ(ep → J ψX) = (8.8±2.0±2.2) nb is determined for 30 GeV ≤ Wγp ≤ 180 GeV and Q2 ≲ 4 GeV2. Using the flux of quasi-real photons with Q2 ≲ 4 GeV2, a total production cross section of σ(γp → J/ψX) = (56±13±14) nb is derived at an average Wγp=90 GeV. The distribution of the squared momentum transfer t from the proton to the J ψ can be fitted using an exponential exp(-b∥t∥) below a ∥t∥ of 0.75 GeV2 yielding a slope parameter of b = (4.7±1.9) GeV-2. © 1994.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Ahmed T; Aid S; Andreev V; Andrieu B; Appuhn RD; Arpagaus M; Babaev A; Baehr J; Bán J; Baranov P
  • Start Page

  • 507
  • End Page

  • 518
  • Volume

  • 338
  • Issue

  • 4