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  • G Abbiendi, K Ackerstaff, +141 authors Heisenberg Fellow
  • 1999
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 α em ,(More)
Production of events with hadronic and leptonic final states has been measured in e + e − collisions at centre-of-mass energies of 130–172 GeV, using the OPAL detector at LEP. Cross-sections and leptonic forward-backward asymmetries are presented, both including and excluding the dominant production of radiative Zγ events, and compared to Standard Model(More)
  • G Abbiendi, K Ackerstaff, +164 authors Heisenberg Fellow
  • 1997
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)
Helicity density matrix elements for inclusive K * (892) 0 mesons from hadronic Z 0 decays have been measured over the full range of K * 0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x p values above 0.3, with the matrix element ρ 00 rising to 0.66 ±(More)
Cross-sections for hadronic and leptonic two-fermion events, and leptonic forward-backward asymmetries, have been measured in e + e ? collisions at a centre-of-mass energy of 161 GeV, using the OPAL detector at LEP. Results are presented both including and excluding the dominant production of radiative Z 0 events. We have measured R b , the ratio of the(More)
The CRIPT project brings together several Canadian institutions, concerned with the detection of Special Nuclear Materials (SNM), addressing a requirement at ports-of-entry for detection of SNM in the many thousands of containers that flow into and out of Canada every day, while at the same time providing a way of monitoring the contents of nuclear waste(More)
New measurements are presented of the photon structure function F 2 (x; Q 2) at four values of Q 2 between 9 and 59 GeV 2 based on data collected with the OPAL detector at centre-of-mass energies of 161?172 GeV, with a total integrated luminosity of 18.1 pb ?1. The evolution of F 2 with Q 2 in bins of x is determined in the Q 2 range from 1.86 to 135 GeV 2(More)
We have searched for unstable neutral and charged heavy leptons, N and L , and for excited states of neutral and charged leptons, , e , and , 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(More)