Journal article
Exclusive electroproduction of J/psi mesons at HERA
Nuclear physics. B, Vol.695(1-2), pp.3-37
09/06/2004
DOI: 10.1016/j.nuclphysb.2004.06.034
Abstract
The exclusive electroproduction of J/psi mesons, ep --> epJ/psi, has been studied with the ZEUS detector at HERA for virtualities of the exchanged photon in the ranges 0.15 < Q(2) < 0.8 GeV2 and 2 < Q(2) < 100 GeV2 using integrated luminosities of 69 and 83 pb(-1), respectively. The photonproton centre-of-mass energy was in the range 30 < W < 220 GeV and the squared four-momentum transfer at the proton vertex \t\ < 1 GeV2. The cross sections and decay angular distributions are presented as functions of Q(2), W and t. The effective parameters of the pomeron trajectory are in agreement with those found in J/psi photoproduction. The spin-density matrix elements, calculated from the decay angular distributions, are consistent with the hypothesis of s-channel helicity conservation. The ratio of the longitudinal to transverse cross sections, sigma(L)/sigma(T), grows with Q(2), whilst no dependence on W or t is observed. The results are in agreement with perturbative QCD calculations and exhibit a strong sensitivity to the gluon distribution in the proton. (C) 2004 Elsevier B.V. All rights reserved.
Details
- Title: Subtitle
- Exclusive electroproduction of J/psi mesons at HERA
- Creators
- ZEUS CollaborationJ Repond (Contributor)
- Resource Type
- Journal article
- Publication Details
- Nuclear physics. B, Vol.695(1-2), pp.3-37
- DOI
- 10.1016/j.nuclphysb.2004.06.034
- ISSN
- 0550-3213
- eISSN
- 1873-1562
- Publisher
- Elsevier
- Number of pages
- 35
- Language
- English
- Date published
- 09/06/2004
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627295202771
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