I . P . Duerdoth

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Cross-sections and angular distributions for hadronic and lepton pair final states in e+e− collisions at a centre-of-mass energy near 189 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. The results are used to measure the energy dependence of the electromagnetic coupling constant αem, and(More)
This paper describes the silicon microstrip modules in the barrel section of the SemiConductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The module requirements, components and assembly techniques are given, as well as first results of the module performance on the fully-assembled barrels that make up the detector being(More)
The measurement of small–angle Bhabha scattering is used to determine the luminosity at the OPAL interaction point for the LEP I data recorded between 1993 and 1995. The measurement is based on the OPAL Silicon-Tungsten Luminometer which is composed of two calorimeters encircling the LEP beam pipe, on opposite sides of the interaction point. The luminometer(More)
We present measurements of triple gauge boson coupling parameters using data recorded by the OPAL detector at LEP2 at a centre-of-mass energy of 172 GeV. A total of 120W-pair candidates has been selected in the qqqq, qqlνl and lνll ′ νl′ decay channels, for an integrated luminosity of 10.4 pb. We use these data to determine several different anomalous(More)
A search is described to detect charged Higgs bosons via the process ee → HH, using data collected by the OPAL detector at center-of-mass energies of 130−172 GeV with a total integrated luminosity of 25 pb. The decay channels are assumed to be H → qq and H → τντ . No evidence for charged Higgs boson production is observed. The lower limit for its mass is(More)
We have searched for unstable neutral and charged heavy leptons, N and L, and for excited states of neutral and charged leptons, ν, e, μ and τ, in e+e− collisions at centre-of-mass energies of 170 and 172 GeV using the OPAL detector at LEP. No evidence for their existence was found. From the analysis of charged-current decays of pair-produced unstable heavy(More)
QCD coherence effects are studied based on measurements of correlations of particles with either restricted transverse momenta, pT < p cut T , where pT is defined with respect to the thrust axis, or restricted absolute momenta, p ≡ |p| < p , using about four million hadronic Z decays recorded at LEP with the OPAL detector. The correlations are analyzed in(More)
A search for the Standard Model Higgs boson has been performed with the OPAL detector at LEP based on the full data sample collected at √ s ≈ 192–209 GeV in 1999 and 2000, corresponding to an integrated luminosity of approximately 426 pb. The data are examined for their consistency with the background-only hypothesis and various Higgs boson mass hypotheses.(More)
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 438 pb at centre-of-mass energies of √ s =192 – 209 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level lower limit on the scalar top quark mass is 97.6 GeV if the mixing angle between the supersymmetric(More)