Eur. Phys. J. C 24, 345-360 (2002)
Exclusive photoproduction of mesons at HERAThe ZEUS collaboration
(Received: 1 February 2002 / Published online: 22 May 2002)
The exclusive photoproduction of mesons, , has been studied in ep collisions with the ZEUS detector at HERA, in the kinematic range GeV, where is the photon-proton centre-of-mass energy. The mesons were reconstructed in the muon and the electron decay channels using integrated luminosities of 38 and 55 , respectively. The helicity structure of production shows that the hypothesis of s-channel helicity conservation is satisfied within two standard deviations. The total cross section and the differential cross-sec tion , where t is the squared four-momentum transfer at the proton vertex, are presented as a function of W, for |t|<1.8 GeV 2. The t distribution exhibits an exponential shape with a slope parameter increasing logarithmically with W with a value at . The effective parameters of the Pomeron trajectory are and .
© Società Italiana di Fisica, Springer-Verlag 2002