M. Boutemeur

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Searches for first generation scalar and vector leptoquarks, and for squarks in R-parity violating SUSY models with the direct decay of the squark into Standard Model particles, have been performed using e + e − collisions collected with the OPAL detector at LEP at e + e − centre-of-mass energies between 189 and 209 GeV. No excess of events is found over(More)
Searches for the neutral Higgs bosons h 0 and A 0 are used to obtain limits on the Type II Two Higgs Doublet Model (2HDM(II)) with no CP–violation in the Higgs sector and no additional particles besides the five Higgs bosons. The analysis combines approximately 170 pb −1 of data collected with the OPAL detector at √ s ≈ 189 GeV with previous runs at √ s ≈ m(More)
Monitored Drift Tube (MDT) chambers will constitute the large majority of precision detectors in the Muon Spectrometer of the ATLAS experiment at the Large Hadron Collider at CERN. For commissioning and calibration of MDT chambers, a Cosmic Ray Measurement Facility is in operation at Munich University. The objectives of this facility are to test the(More)
Gluon jets with a mean energy of 22 GeV and purity of 95% are selected from hadronic Z 0 decay events produced in e + e − annihilations. A subsample of these jets is identified which exhibits a large gap in the rapidity distribution of particles within the jet. After imposing the requirement of a rapidity gap, the gluon jet purity is 86%. These jets are(More)
Searches for unstable neutral and charged heavy leptons, N and L ± , and for excited states of neutral and charged leptons, ν * , e * , µ * , and τ * , have been performed in e + e − collisions using data collected by the OPAL detector at LEP. The data analysed correspond to an integrated luminosity of about 58 pb −1 at a centre-of-mass energy of 183 GeV,(More)
A search for pair produced scalar fermions with couplings that violate R-parity has been performed using a data sample corresponding to an integrated luminosity of 56 pb −1 at a centre-of-mass energy of √ s = 183 GeV collected with the OPAL detector at LEP. An important consequence of R-parity breaking interactions is that the lightest supersymmet-ric(More)
Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 × 10 6 hadronic Z 0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near(More)
A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at √ s = 189–209 GeV, corresponding to an integrated luminosity of approximately 600 pb −1. Charged Higgs bosons are assumed to be pair-produced and to decay into q¯ q, τ ν τ(More)
Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass of the Z 0 boson with the OPAL detector at LEP. The strong coupling α s is extracted by comparing data and QCD predictions for event shape observables at average reduced centre-of-mass energies ranging from 24 GeV to 78 GeV, and the(More)