A Study of Direct Photon Production in Hadronic Interactions

High energy physics

Maxwell, Robert Alan

University:University of Glasgow

关键词: High energy physics;   

Others  :  http://theses.gla.ac.uk/77447/1/10991911.pdf

来源: University of Glasgow

【 摘 要 】

This thesis presents results on direct photon production in pi--p and pi+-p interactions at an incident beam momentum of 280 GeV/c, using data recorded by CERN experiment WA70 at the Omega Prime Spectrometer. The direct photon cross-section, and the ratio of direct photon and pi cross-sections, is measured over the Pt range 4-7 GeV/c and the Feynman X range -0.4 to 0.4. Chapter 1 gives an account of the theoretical framework used to describe direct photon production, together with a brief review of recent experimental results. Chapter 2 describes the experimental apparatus used by WA70, with particular emphasis on the high-granularity electromagnetic calorimeter constructed specifically for the experiment. Chapter 3 discusses the reconstruction programs used to process the raw data from the Omega Prime Spectrometer and calorimeter prior to performing any physics analysis. Chapter 4 describes the sequence of cuts used to isolate the pi0 and direct photon signals in the experimental data. In Chapter 5, the efficiencies of detection of pi0s and direct photons, and the residual backgrounds in the direct photon signal, are determined. The simulation programs used to measure these efficiencies and backgrounds are described, together with the methods used when the simulation programs could not be applied. Finally, in Chapter 6 the cross-sections for direct photon and pi0 production and the ratio of the cross-sections are presented. The pi0 cross-sections are compared to the parametrised results from other experiments, and the direct photon cross-sections are compared with the predictions of next-to-leading order perturbative quantum chromodynamics.