Giovanni Abbiendi

Tests of the standard model and constraints on new physics from measurements of fermion-pair production at 189 GeV at LEP

Abstract.Cross-sections and angular distributions for hadronic and lepton-pair final states in e + e- collisions at centre-of-mass energies between 189 GeV and 209 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. The measurements are used to determine the electromagnetic coupling constant

Decay-mode independent searches for new scalar bosons with the OPAL detector at LEP

\alpha_{\mathrm{em}}

Measurement of the strange spectral function in hadronic tau decays

at LEP 2 energies. In addition, the results are used together with OPAL measurements at 91-183 GeV within the S-matrix formalism to determine the

Search for higgs bosons in e+e- collisions at 183-GeV

\gamma

Measurement of the mass and width of the

-Z interference term and to make an almost model-independent measurement of the Z mass. Limits on extensions to the Standard Model described by effective four-fermion contact interactions or the addition of a heavy Z’ boson are also presented.

W

Abstract. This paper describes topological searches for neutral scalar bosons S0 produced in association with a Z0 boson via the Bjorken process

boson

e^+e^- \to{\rm S}^0{}{\rm Z}^0

Searches for gauge-mediated supersymmetry breaking topologies in e+ e- collisions at LEP2

at centre-of-mass energies of 91 GeV and 183-209 GeV. These searches are based on studies of the recoil mass spectrum of

W+W− production and triple gauge boson couplings at LEP energies up to 183 GeV

{\rm Z}^0 \to e^+e^-

Determination of alpha(s) using jet rates at LEP with the OPAL detector

and