Philip Burrows

Abstract:

The unique SLD CGD vertex detector combined with the highly-polarised electron beam allow us to search for an anomalous chromomagnetic coupling of the b-quark, as well as P-odd, T-N-odd and CP-odd processes at the b (b) over barg vertex.

Abstract:

The structure of e+e-→bb̄g events was studied using 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 b. Distributions of the gluon energy and polar angle were measured over the full kinematic range for the first time, and compared with perturbative QCD predictions. The energy distribution is potentially sensitive to an anomalous b chromomagnetic moment κ. We measured κ to be consistent with zero and set the first limits on its value: -0.17<κ<0.11 at 95% C.L. ©1999 The American Physical Society.

Abstract:

We have measured the differential production cross sections as a function of scaled momentum xp=2p/Ec.m. of the identified hadron species π⁺, K⁺, K⁰, K*⁰, φ, p, Λ⁰, and of the corresponding antihadron species in inclusive hadronic Z⁰ decays, as well as separately for Z⁰ decays into light (u, d, s), c and b flavors. Clear flavor dependences are observed, consistent with expectations based upon previously measured production and decay properties of heavy hadrons. These results were used to test the QCD predictions of Gribov and Lipatov, the predictions of QCD in the modified leading logarithm approximation with the ansatz of local parton-hadron duality, and the predictions of three fragmentation models. The ratios of production of different hadron species were also measured as a function of xp and were used to study the suppression of strange meson, strange and non-strange baryon, and vector meson production in the jet fragmentation process. The light-flavor results provide improved tests of the above predictions, as they remove the contribution of heavy hadron production and decay from that of the rest of the fragmentation process. In addition we have compared hadron and antihadron production as a function of xp in light quark (as opposed to antiquark) jets. Differences are observed at high xp, providing direct evidence that higher-momentum hadrons are more likely to contain a primary quark or antiquark. The differences for pseudoscalar and vector kaons provide new measurements of strangeness suppression for high-xp fragmentation products. ©1999 The American Physical Society.