A study of W boson properties with four-jet W^+W^- events at LEP

<p>In this thesis I present a study of W pair production in e⁺e^- annihilation using fully hadronic W⁺W^- events. Data collected by the L3 detector at LEP in 1996-1998, at collision center-of-mass energies between 161 and 189 GeV, was used in my analysis.</p> <p>Analysis of the total and differential W⁺W^- cross sections with the resulting sample of 1,932 W⁺W^- → qqqq event candidates allowed me to make precision measurements of a number of properties of the W boson. I combined my measurements with those using other W⁺W^- final states to obtain stringent constraints on the W boson's couplings to fermions, other gauge bosons, and scalar Higgs field by measuring the total e⁺e^- → W⁺W^- cross section and its energy dependence</p> <p>σ(e⁺e^- → W⁺W^-) =</p> <p>{2.68^+0.98_-0.67(stat.)± 0.14(syst.) pb, √s = 161.34 GeV</p> <p>{12.04^+1.38_-1.29(stat.)± 0.23(syst.) pb, √s = 172.13 GeV</p> <p>{16.45 ± 0.67(stat.) ± 0.26(syst.) pb, √s = 182.68 GeV</p> <p>{16.28 ± 0.38(stat.) ± 0.26(syst.) pb, √s = 188.64 GeV</p> <p>the fraction of W bosons decaying into hadrons</p> BR(W →qq') = 68.72 ± 0.69(stat.) ± 0.38(syst.) %, <p>invisible non-SM width of the W boson</p> Γ^invisible_W less than MeV at 95% C.L., <p>the mass of the W boson</p> M_W = 80.44 ± 0.08(stat.)± 0.06(syst.) GeV, <p>the total width of the W boson</p> Γ_W = 2.18 ± 0.20(stat.)± 0.11(syst.) GeV, <p>the anomalous triple gauge boson couplings of the W</p> <p>Δg^Z₁ = 0.16^+0.13_-0.20(stat.) ± 0.11(syst.)</p> <p>Δk_γ = 0.26^+0.24_-0.33(stat.) ± 0.16(syst.)</p> <p>λ_γ = 0.18^+0.13_-0.20(stat.) ± 0.11(syst.)</p> <p>No significant deviations from Standard Model predictions were found in any of the measurements.</p>