The OPAL collaboration — Page 7

arXiv1999

A study of B0s meson oscillation using hadronic Z0 decays containing leptons

A sample of Z decays containing b-flavoured hadrons is tagged using leptons, and events having precise proper time measurements are selected. These events are used to study Bs oscillations. using the lepton to tag the decay b-flavour and jet charge or a second lepton, where available, to determine the produced b-flavour. The flavour (b or b-bar) at decay is determined from the lepton charge while the flavour at production is determined from jet charge or the charge of a second lepton, where available. The experiment was not able to resolve the oscillatory behaviour, and we deduce that the Bs oscillation frequency Delta(ms)> 5.2ps-1 at the 95% confidence level.

hep-ex↗

arXiv1999

Search for Higgs Bosons and Other Massive States decaying into two Photons in e+e- Collisions at 189 GeV

A search is described for the generic process e+e- to X Y, where X is a neutral heavy scalar boson decaying into a pair of photons, and Y is a neutral heavy boson (scalar or vector) decaying into a fermion pair. The search is motivated mainly by the cases where either X, or both X and Y, are Higgs bosons. In particular, we investigate the case where X is the Standard Model Higgs boson and Y the Z0 boson. Other models with enhanced Higgs boson decay couplings to photon pairs are also considered. The present search combines the data set collected by the OPAL collaboration at 189 GeV collider energy, having an integrated luminosity of 182.6pb-1, with data samples collected at lower energies. The search results have been used to put 95% confidence level bounds, as functions of the mass of X, on the product of the cross-section and the relevant branching ratios, both in a model independent manner and for the particular models considered.

hep-ex↗