Speaker
Description
The photoproduction of isolated photons has been measured using diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 < $E_T^\gamma$ < 15 GeV and
−0.7 < $\eta^\gamma$ < 0.9, inclusively and also with a jet with transverse-energy and pseudorapidity in the ranges 4 < $E_T^{jet}$ < 35 GeV and −1.5 < $\eta^{jet}$ < 1.8, using a total integrated electron-proton 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 $z_{pom}^{meas}$ > 0.9 where $z_{pom}^{meas}$ is the fraction of the longitudinal momentum of the colourless “Pomeron” exchange that is transferred to the photon-jet final state, giving evidence for direct-Pomeron interactions.
| Experimental Collaboration | ZEUS |
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