ATLAS

Abstract:

We present measurements of correlated bb̄ cross sections, μ-μ, correlations, the average B0B̄0 mixing parameter χ̄, and a limit on the CP-violating parameter ∈B. For these measurements, we use muon pairs from bb double semileptonic decays. The data used in this analysis were taken with the Collider_Detector at Fermilab and represent an integrated luminosity of 17.4±0.6 pb-1. The results concerning bb̄ production correlations are compared to predictions of next-to-leading order QCD computations.

Abstract:

Using the ZEUS detector at the HERA electron-proton collider, we have searched for lepton flavor violation in ep collisions at a center-of-mass energy (√s) of 300 GeV. Events of the type e + p → ℓ + X with a final-state lepton of high transverse momentum, ℓ = μ or τ, were sought. No evidence was found for lepton flavor violation in the combined 1993 and 1994 data samples, for which the integrated luminosities were 0.84 pb-1 for e-p collisions and 2.94 pb-1 for e+p collisions. Limits on coupling vs. mass are provided for leptoquarks and R-parity violating squarks. For flavor violating couplings of electromagnetic strength, we set 95% confidence level lower limits on leptoquark masses between 207 GeV and 272 GeV, depending on the leptoquark species and final-state lepton. For leptoquark masses larger than 300 GeV, limits on flavor-changing couplings are determined, many of which supersede prior limits from rare decay processes. © Springer-Verlag 1997.