Elastic and proton-dissociative photoproduction of rho(0), phi and J/psi vector mesons (gamma p --> Vp, gamma p --> VN, respectively) have been measured in e(+)p interactions at HERA up to -t = 3 GeV(2), where t is the four-momentum transfer squared at the photon-vector-meson vertex. The analysis is based on a data sample in which photoproduction reactions were tagged by detection of the scattered positron in a special-purpose calorimeter. This limits the photon virtuality, Q(2), to values less than 0.01 GeV2, and selects a gamma p average center-of-mass energy of (W) = 94 GeV. Results for the differential cross sections, d sigma/dt, for rho(0), phi and J/psi mesons are presented and compared to the results of recent QCD calculations. Results are also presented for the t-dependence of the pion-pair invariant-mass distribution in the rho(0) mass region and of the spin-density matrix elements determined from the decay-angle distributions. The Pomeron trajectory has been derived from measurements of the W dependence of the elastic differential cross sections d sigma/dt for both rho(0) and phi mesons.

Measurement of diffractive photoproduction of vector mesons at large momentum transfer at HERA

SACCHI, Roberto;CIRIO, Roberto;COSTA, Marco;MONACO, Vincenzo;PERONI, Cristiana;SOLANO, Ada Maria;
2000-01-01

Abstract

Elastic and proton-dissociative photoproduction of rho(0), phi and J/psi vector mesons (gamma p --> Vp, gamma p --> VN, respectively) have been measured in e(+)p interactions at HERA up to -t = 3 GeV(2), where t is the four-momentum transfer squared at the photon-vector-meson vertex. The analysis is based on a data sample in which photoproduction reactions were tagged by detection of the scattered positron in a special-purpose calorimeter. This limits the photon virtuality, Q(2), to values less than 0.01 GeV2, and selects a gamma p average center-of-mass energy of (W) = 94 GeV. Results for the differential cross sections, d sigma/dt, for rho(0), phi and J/psi mesons are presented and compared to the results of recent QCD calculations. Results are also presented for the t-dependence of the pion-pair invariant-mass distribution in the rho(0) mass region and of the spin-density matrix elements determined from the decay-angle distributions. The Pomeron trajectory has been derived from measurements of the W dependence of the elastic differential cross sections d sigma/dt for both rho(0) and phi mesons.
2000
14
213
238
http://dx.doi.org/10.1007/s100520050748
ZEUS; ELASTIC-SCATTERING; LARGE-T; QCD; ELECTROPRODUCTION; J/PSI; RHO(0); PHOTON; SHRINKAGE; HYDROGEN
J. Breitweg;S. Chekanov;M. Derrick;D. Krakauer;S. Magill;B. Musgrave;A. Pellegrino;J. Repond;R. Stanek;R. Yoshida;M. C. K.;G. Abbiendi;F. ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/109641
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