Phenomenology of QCD and electroweak processes

Abstract

A phenomenological study is made of several aspects of the standard model (and beyond) in the context of collider physics. These calculations are performed in the framework of Quantum Chromodynamics (QCD) and the standard Elec-troweak theory in an attempt to understand the underlying gauge theory more fully. In chapter 2, a precision QCD and electroweak calculation is performed to predict the high transverse-momentum distribution of the intermediate vector bosons produced in pṕ collisions. Calculated cross-sections are compared with data from the CERN collider and predictions are made for the Tevatron, LHC and SSC. Theoretical uncertainties, due to scale and structure function ambiguities, are estimated. In chapter 3, the equivalent photon approximation (or EPA) is studied at high energies to determine the accuracy of the approximation. An exact calculation of the process e + q → e + q + γ is performed and compared with an approximate calculation of the process γ+q → γ+q , where the initial-state photon is produced (using the EPA) from an initial-state electron. The test is carried out for the cases where the final-state electron are tagged and untagged. At high energies, the approximation is accurate to within 10%. In chapter 4, deep inelastic Compton scattering is investigated at energies of the HERA ep collider. A study of the production rate is made to determine the feasibility of measurement at HERA and it is clear that for pT < 50 GeV/c the cross-section will be measurable. In addition, studies are made to determine the efficiency of this process as a probe of the proton structure functions. The cross-section is only weakly dependent on the structure functions. In chapter 5, the production of charged Higgs scalars is considered at hadron colliders. The fully inclusive cross-section for charged Higgs scalars is calculated and compared with the associated W boson cross-section. The generic process g+b →b+t + t, which may proceed through an intermediate charged Higgs (or W) or through QCD processes, is studied and the Higgs cross-sections are compared with the W and QCD cross-sections.