2 resultados para 189-1171C
em CaltechTHESIS
Resumo:
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.
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
σ(e+e- → W+W-) =
{2.68+0.98-0.67(stat.)± 0.14(syst.) pb, √s = 161.34 GeV
{12.04+1.38-1.29(stat.)± 0.23(syst.) pb, √s = 172.13 GeV
{16.45 ± 0.67(stat.) ± 0.26(syst.) pb, √s = 182.68 GeV
{16.28 ± 0.38(stat.) ± 0.26(syst.) pb, √s = 188.64 GeV
the fraction of W bosons decaying into hadrons
BR(W →qq') = 68.72 ± 0.69(stat.) ± 0.38(syst.) %,invisible non-SM width of the W boson
ΓinvisibleW less than MeV at 95% C.L.,the mass of the W boson
MW = 80.44 ± 0.08(stat.)± 0.06(syst.) GeV,the total width of the W boson
ΓW = 2.18 ± 0.20(stat.)± 0.11(syst.) GeV,the anomalous triple gauge boson couplings of the W
ΔgZ1 = 0.16+0.13-0.20(stat.) ± 0.11(syst.)
Δkγ = 0.26+0.24-0.33(stat.) ± 0.16(syst.)
λγ = 0.18+0.13-0.20(stat.) ± 0.11(syst.)
No significant deviations from Standard Model predictions were found in any of the measurements.
Resumo:
The thermal reaction between nitrogen dioxide and acetaldehyde in the gas phase was investigated at room temperature and atmospheric pressure. The initial rate of disappearance of nitrogen dioxide was 1.00 ± 0.03 order with respect to nitrogen dioxide and 1.00 ± 0.07 order with respect to acetaldehyde. An initial second order rate constant of (8.596 ± 0.189) x 10-3 1.mole-1 sec-1 was obtained at 22.0 ± 0.1 °C and a total pressure of one atmosphere. The activation energy of the reaction was 12,900 cal/mole in the temperature range between 22°C and 122°C.
The products of the reaction were nitric oxide, carbon dioxide, methyl nitrite, nitromethane and a trace amount of trans-dimeric nitrosomethane. The addition of nitric oxide increased the rate of formation of nitromethane and decreased the rate of formation of methyl nitrite. There were no measurable surface effects due to the addition of glass wool or glass beads to the reactor.
Reactants and products were analyzed by gas chromatography. A mechanism was proposed incorporating the principal features of the reaction.