Measurement of the cross-section for the reaction $\\gamma p \\to J/\\psi p$ with the ZEUS detector at HERA
Journal
Physics Letters
Journal Volume
B350
Pages
120-134
Date Issued
1995-03
Author(s)
Derrick, M. et al.(ZEUS Collaboration)
Abstract
This paper reports the cross section measurements for the process ep → e J/ψ p for Q2< 4 GeV2at s = 296 GeV, based on an integrated luminosity of about 0.5 pb-1, using the ZEUS detector. The J/ψ was detected in its e+e-and μ+μ-decay modes. The photoproduction cross section was measured to be 52-12 +7± 10 nb at an average γp centre of mass energy of 67 GeV and 71-20 +13±12 nb at 114 GeV. The significant rise of the cross section compared to lower energy measurements is not in agreement with VDM models, but can be described by QCD inspired models if a rise in the gluon momentum density at low x in the proton is assumed. © 1995.
SDGs
Type
journal article