Elastic and inelastic photoproduction of <script type="math/tex">J/\psi</script> mesons at HERA

Aid, S.; De Roeck, A.; de Wolf, E.A.; Van Mechelen, P.; Jung, H.; [et al.]

doi:10.1016/0550-3213(96)00274-X

Title

Elastic and inelastic photoproduction of $J/\psi$ mesons at HERA

Author

Aid, S.

De Roeck, A.

de Wolf, E.A.

Van Mechelen, P.

Jung, H.

[et al.]

Abstract

Results on J/psi production in ep interactions in the Hi experiment at HERA are presented. The J/psi mesons are produced by almost real photons (Q(2) approximate to 0) and detected via their leptonic decays. The data have been taken in 1994 and correspond to an integrated luminosity of 2.7 pb(-1). The yp cross section for elastic J/psi production is observed to increase strongly with the center of mass energy. The cross section for diffractive J/psi production with proton dissociation is found to be of similar magnitude as the elastic cross section. Distributions of transverse momentum and decay angle are studied and found to be in accord with a diffractive production mechanism. For inelastic J/psi production the total yp cross section, the distribution of transverse momenta, and the elasticity of the J/psi are compared to NLO QCD calculations in a colour singlet model and agreement is found. Diffractive psi' production has been observed and a first estimate of the ratio to J/psi production in the HERA energy regime is given.

Language

English

Source (journal)

Nuclear physics : B / Institute of Physics [London] - Amsterdam, 1967, currens

Publication

Amsterdam : North-Holland , 1996

ISSN

0550-3213 [print]

1873-1562 [online]

DOI

10.1016/0550-3213(96)00274-X

Volume/pages