Philip Burrows

Abstract:

The improved direct measurement of Ab at the Z⁰ pole using a lepton tag was presented. The measurements were carried out using identified charged leptons from semileptonic decays. The results obtained were found to be in agreement with the standard model predictions and were insensitive to uncertainties in standard model parameters and the top quark and Higgs boson masses.

Abstract:

The structure of 3-jet e⁺ e^- → bb̄g events has been studied using hadronic Z⁰ decays recorded in the SLC Large Detector experiment at SLAC. Three-jet final states were selected and the charge-coupled-device-based vertex detector was used to identify two of the jets as b or b̄; the remaining jet in each event was tagged as the gluon jet. Distributions of the gluon energy and polar angle with respect to the electron beam were measured over the full kinematic range, and used to test the predictions of perturbative QCD. We find that beyond-leading-order QCD calculations are needed to reproduce the features seen in the data. The energy distribution is sensitive to an anomalous b chromomagnetic moment K at the bb̄g vertex. We measured κ to be consistent with zero and set 95% confidence level limits on its value, -0.06<κ<0.04. © 2002 The American Physical Society.

Abstract:

A search for B0s-B̄0s oscillations is performed using a sample of 400 000 hadronic Z0 decays collected by the SLAG Large Detector experiment. The B0s candidates are reconstructed in the B0s→D-sX channel with D-s→Φπ-, K*0K-. The B0s production flavor is determined using the large forward-backward asymmetry of polarized Z0→bb̄ decays and charge information in the hemisphere opposite that of the B0s candidate. The decay flavor is tagged by the charge of the D ±s. From a sample of 361 candidates with an average B0s purity of 40%, we exclude the following values of the oscillation frequency: Δms<1.4 ps-1 and 2.4<Δms <5.3 ps-1 at the 95% confidence level. © 2002 The American Physical Society.