The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 < ETγ< 15 GeV and -0.7 < ηγ< 0.9, inclusively, and also with a jet with transverse energy and pseudorapidity in the ranges 4 < ETjet< 35 GeV and -1.5 < ηjet< 1.8, using a total integrated electronproton luminosity of 456 pb-1. A number of kinematic variables were studied and compared to predictions from the RAPGAP Monte Carlo model. An excess of data is observed above the RAPGAP predictions for zâmeas> 0.9, where zâmeasis the fraction of the longitudinal momentum of the colorless "Pomeron" exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.
Studies of the diffractive photoproduction of isolated photons at HERA
Capua, M.;Mastroberardino, A.;Schioppa, M.;Tassi, E.;
2017-01-01
Abstract
The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 < ETγ< 15 GeV and -0.7 < ηγ< 0.9, inclusively, and also with a jet with transverse energy and pseudorapidity in the ranges 4 < ETjet< 35 GeV and -1.5 < ηjet< 1.8, using a total integrated electronproton luminosity of 456 pb-1. A number of kinematic variables were studied and compared to predictions from the RAPGAP Monte Carlo model. An excess of data is observed above the RAPGAP predictions for zâmeas> 0.9, where zâmeasis the fraction of the longitudinal momentum of the colorless "Pomeron" exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.