Characteristics of Hadronic States Observed in High-Energy Diffractive Photoproduction in Hydrogen
1982260 pages
Supervisor:
Thesis: PhD - Colorado U.
DOI:
Report number:
- FERMILAB-THESIS-1982-09,
- UMI-82-29821,
- COLO-HEP-57
Experiments:
Citations per year
Abstract:
A large multi-particle spectrometer was constructed at the Fermi National Accelerator Laboratory to study the interaction of high energy photons with protons in a fixed liquid hydrogen target. The energy of the incident photons was measured for each event ranging from 40 to 160 GeV. Data was accumulated for events characterized by the presence of hadronic particles in the spectrometer. An on-line trigger processor identified protons in the recoil spectrometer surrounding the target and calculated the missing mass, selecting only those events with a missing mass between 2 and 11 GeV.The data sample thus consists of high mass diffractive events containing hadronic particles in the final state. A drift chamber system consisting of four separate modules containing a total of 29 active planes was used to reconstruct the momentum components of all charged particles present within the acceptance of the spectrometer. Two large volume gas Cerenkov counters were used to identify electrons. The recoil spectrometer provided sufficient information to reconstruct the 4-momentum of all charged particles within its acceptance. Using this information events were selected which contained a single charged particle in the recoil spectrometer identified as a proton. A minimum of three charged particles was required in the forward spectrometer. Electrons were not counted.) Only charged particles were used in the analysis. A jet-like structure is observed in the center of mass. This structure is characterized by a decrease in the sphericity and a limiting value for the transverse momentum as the missing mass increases. Comparisons are made with other hadronic and e+e- annihilation experiments. The Feynman X, rapidity, and Pt inclusive distributions are studied as a function of the missing mass in the central and photon fragmentation regions. Fits are made to functional forms motivated by QeD counting rules. The results are in good agreement with the theory in the large Feynman X region. Scaling is observed in this region. In the central region scaling violations are observed and measured as a function of the center of mass energy.- THESIS
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