A search for doubly charged higgs production in z0 decays

Contains fulltext : 124394.pdf (preprint version ) (Open Access

Evidence for chain - like production of strange baryon pairs in jets

Contains fulltext : 124372.pdf (preprint version ) (Open Access

Measurement of the B0 and B+ lifetimes

Contains fulltext : 124375.pdf (preprint version ) (Open Access

A Study of the electric charge distributions of quark and gluon jets in hadronic Z0 decays

Contains fulltext : 124406.pdf (preprint version ) (Open Access

A Measurement of the electroweak couplings of up and down type quarks using final state photons in hadronic z0 decays

The production rate of final state photons in hadronic Z0 decays is measured as a function of ycut = Mij2/Ecm2 the jet resolution parameter and minimum mass of the photon-jet system. Good agreement with the theoretical expectation from an O(ααs) matrix element calculation is observed. Comparing the measurement and the prediction for ycut = 0.06, where the experimental systematic and statistical errors and the theoretical uncertainties are small, and combining this measurement with our result for the hadronic width of the Z0, we derived partial widths of up and down type quarks to be Γu = 333 ± 55 ± 72 MeV and Γd = 358 ± 37 ± 48 MeV in agreement with the standard model expectations. We compare our yield with the QCD shower models including photon radiation. At low γcut JETSET underestimates the photon yield, and ARIADNE describes the production rate well

A Search for scalar leptoquarks in Z0 decays

Contains fulltext : 125110.pdf (preprint version ) (Open Access

Decay mode independent search for a light Higgs boson and new scalars

Contains fulltext : 125114.pdf (preprint version ) (Open Access

A measurement of photon radiation in lepton pair events from Z0 decays

We have measured the photon yield in lepton pair events recorded by the OPAL detector in a data sample corresponding to an integrated luminosity of 7.1 pb−1 at centre-of-mass energies between 88 GeV and 94 GeV. The results are compared to QED expectations for initial and final state photon radiation. No anomalous photon yield has been found, and stringent limits on the branching ratio for exotic radiative three body Z0 decays into a photon and a pair of leptons are obtained. We also place limits on possible Z0 decays into a photon and a resonance X with subsequent decays of X into a pair of leptons. Acollinear μ+μ− events with missing momentum along the beam direction are identified as events with hard initial state photon radiation and used to measure an average cross section of 15 ±86 pb for e+e− annihilation into μ+μ−, in the so far untested range of centre-of-mass energies between 60 GeV and 84 GeV. This value is consistent with a cross section of 24 pb, expected from Z0 and photon exchange

A Study of K0(s) K0(s) Bose-Einstein correlations in hadronic Z0 decays

Contains fulltext : 124404.pdf (publisher's version ) (Open Access