Prompt Photon Production in Photoproduction at HERA
Proceedings of the XVI International Workshop on Deep-Inelastic Scattering and Related Topics
This thesis presents measurement of the production of prompt photons in photoproduction with the H1 experiment at HERA. The analysis is based on the data taken in the years 2004-2007, with a total integrated luminosity of 340 pb −1 . The main difficulty of the measurement comes from the high background of neutral mesons decaying into photons. It is accounted for with the help of multivariate analysis. Prompt photon cross sections are measured with the low negative four-momentum transfer squared
... um transfer squared Q 2 < 1 GeV 2 and in the inelasticity range 0.1 < y < 0.7 for photons with a transverse energy 6 < E γ T < 15 GeV and in the pseudorapidity range −1.0 < η γ < 2.4 as a function of photons transverse energy and its pseudorapidity. Cross sections for prompt photon events with an additional hadronic jet are measured as a function of the transverse energy and pseudorapidity of the jet and of the momentum fractions x γ and x p of the incident photon and proton carried by the constituents participating in the hard scattering process. Additionally, the transverse correlation between the photon and the jet is studied. The results are compared with predictions of a nextto-leading order calculation and a calculation based on the k T factorisation approach. Neither of calculations is able to describe all the aspects of the measurement.