Measurement of the production cross section for W + γ in the electron channel in √s = 1.8 TeV bar pp collisions

The production cross section times decay branching ratio for W+γ in the electron decay channel in √s = 1.8 TeV bar p-p collisions has been measured using W → eγ data sample obtained from the CDF 1988--1989 Tevatron collider run. For photons in the central region (|ηγ| < 1.1) of the CDF detector with transverse energies ETγ 5.0 GeV and lepton-photon angular separation ΔRellγ > 0.7, eight electron Wγ candidates were observed. From these events, the production cross section times decay branching ratio for the electron sample was measured to be a σ · B(Wγ)exp = 17.0-13.4+13.6(stat. + syst.)pb. The Wγ cross section is sensitive to the anomalous couplings of the W boson. Using the Wγ cross section measurement, the absence of an excess of large ET photons accompanying the production of a W boson enables one to obtain direct limits on anomalous WWγ couplings. The experimental limits on the anomalous couplings was measured to be -7.2 < Δκ < +7.7 (λ = 0) and -3.5 < λ < +3.4 (Δκ = 0) at 95% CL. These experimental limits impose contraints on possible internal structure of the W boson with compositeness scale sensitivity ΛW ≥ 1 TeV for saturation of unitarity, corresponding to probing a distance scale of order LW ≤ 2.0 x 10-4 fm. The experimental limits on anomalous WWγ couplings place bounds on the higher-order electromagnetic moments of the W boson -- the magnetic dipole and electric quadrupole moments and the W boson mean-squared charge radius. The experimental results presented in this thesis are in good agreement with Standard Model expectations