Search for CP violation and b-->sg in inclusive B decays

We present preliminary results on two analyses performed by the SLD Collaboration using inclusive B decays: a search for CP violation and a search for the b --> sg transition.Comment: Talk given at EPS-HEP97 conference, Jerusalem, 19-26 August 1997. LaTex2e document, 5 pages, 1 postscript figure. Anonymous ftp at ftp://ftp.slac.stanford.edu/users/daoudi/slacpub7682.p

The scanning Compton polarimeter for the SLD experiment

For the 1994/95 run of the SLD experiment at SLAC, a Compton polarimeter measured the luminosity-weighted electron beam polarization to be (77.2 +- 0.5)%. This excellent accuracy is achieved by measuring the rate asymmetry of Compton-scattered electrons near the kinematic endpoint. The polarimeter takes data continuously while the electron and positron beams are in collision and achieves a statistical precision of better than 1% in a three minute run. To calibrate the polarimeter and demonstrate its accuracy, many scans are frequently done. These include scans of the laser polarization, the detector position with respect to the kinematic edge, and the laser power. Presented at the Workshop on High Energy Polarimeters at NIKHEF, Amsterdam, The Netherlands on September 9, 1996.Comment: 7 pages, 2 .eps figures, LATE

Tau Physics with Polarized Beams

We present the first results on tau physics using polarized beams. These include measurements of the $\tau$ Michel parameters $\xi$ and $\xi\delta$ and the $\tau$ neutrino helicity $h_\nu$. The measurements were performed using the SLD detector at the Stanford Linear Collider (SLC). (Invited talk at the 1995 International Europhysics Conference on High Energy Physics, Brussels, Belgium, July 27 - August 2, 1995.)Comment: 7 pages, uuencoded gzip-compressed postscript (83 kB) Uncompressed postscript file (855 kB) available via anonymous ftp as ftp://ftp.slac.stanford.edu/users/daoudi/sldtaupb.p

Searches for anomalous effects in the b bbar g coupling

The unique SLD CCD 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 bbar g vertex.Comment: To appear in Proceedings EPS-HEP99; 11 pages including 4 figure

Combined SLD Measurement of Ab at the Z Resonance using Various Techniques

We present a new preliminary combination of measurements of the parity-violation parameter Ab made by the SLD collaboration using various experimental techniques. The techniques differ in detail, but in general a sample of bb events is selected or enhanced by using the topologically reconstructed mass of the separated vertices formed by decaying B hadrons. The direction of the b(bbar) quark is signed by one of four final state tags: jet charge, vertex charge, leptons, or identified K+- from the b vertex. We account for statistical and systematic correlations between the four analyses to arrive at our combined result: Ab=0.905 +/- 0.017 {stat} +/- 0.020 (syst).Comment: 8 pages, 0 figures. Paper submitted to EPS-HEP99 and Lepton-Photon '9

Determination of Electroweak Parameters at the SLC

We present an improved measurement of the left-right cross section asymmetry Alr for Z boson production by e+e- collisions. The measurement was performed at a center-of-mass energy of 91.28 GeV with the SLD detector at the SLAC Linear Collider (SLC) during the 1994-95 running period. The luminosity-weighted average polarization of the SLC electron beam during this run was measured to be (77.23 +/- 0.52)%. Using a sample of 93,644 hadronic Z decays, we measure the pole asymmetry Alr0 to be 0.1512 +/- 0.0042(stat.) +/- 0.0011(syst.) which is equivalent to an effective weak mixing angle of 0.23100 +/- 0.00054(stat.) +/- 0.00014(syst.). We also present a preliminary direct measurement of the Z-lepton coupling asymmetries A_e,A_mu, and A_tau extracted from the differential cross section observed in leptonic Z decays. We combine these results with our previous Alr measurement to obtain a combined determination of the weak mixing angle of 0.23061 +/- 0.00047.Comment: Presented at the 28th International Conference on High Energy Physics, Warsaw, Poland, July 25-31, 1996. 16 Pages, LaTe

Direct Measurement of A_b using Charged Kaons at the SLD Detector

We report a new measurement of A_b using data obtained by SLD in 1997-98. This measurement uses a vertex tag technique, where the selection of a b hemisphere is based on the reconstructed mass of the bottom hadron decay vertex. The method uses the 3D vertexing capabilities of SLD's CCD vertex detector and the small and stable SLC beams to obtain a high b-event tagging efficiency and purity of 78% and 97%, respectively. Charged kaons identified by the CRID detector provide an efficient quark-antiquark tag, with the analyzing power calibrated from the data. We obtain a preliminary result of A_b = 0.997 \pm 0.044 \pm 0.067Comment: 10 pages, 2 figures. Paper contributed to EPS-HEP 99 and Lepton-Photon Symposium 199

Measurement of Rb at SLD

We report a new measurement of Rb=Gamma(Z -> bb)/ Gamma(Z -> hadrons) using a double tag technique where the b selection is based on topological reconstruction of the mass of the B-decay vertex. The measurement was performed using a sample of 150k hadronic Z0 events collected with the SLD at the SLAC Linear Collider during the years 1993-1995. The method utilizes the 3-D vertexing abilities of the SLD CCD pixel vertex detector and the small stable SLC beams to obtain a high b tagging efficiency of 37% for a purity of 97.2%. The high purity reduces the systematics introduced by charm contamination and correlations with Rc. We obtain a result of Rb=0.2176+/-0.0033(stat.)+/-0.0017(syst.)+/-0.0008(Rc). (Presented at the XXXIst Rencontres de Moriond Electroweak Interactions and Unified Theories, Les Arcs, Savoie, France, March 16-23, 1996.)Comment: 12 pages, LaTeX, 3 eps figures, all in tar gzipped fil

Measurements of Z0Z^0 to Heavy-quark couplings at SLD

We present measurements of $Z^0$ to heavy-quark coupling electroweak parameters, $R_b$, $R_c$, and parity-violation parameter $A_c$, from SLD. The measurements are based on approximately 550k hadronic $Z^0$ events collected in 1993-98. Obtained preliminary results of $R_b$ and $R_c$ measurements are $R_b = 0.2159 \pm 0.0014 \pm 0.0014$ and $R_c = 0.1685 \pm 0.0047 \pm 0.0043$. In the $A_c$ measurement, we use four methods to determine the initial-quark charge: combined Kaon charge and Vertex charge, lepton, exclusively reconstructed D*, D-mesons, and a new method using inclusive soft-pion from D*. The preliminary results of these four methods were combined to give $A_c = 0.634 \pm 0.027$.Comment: 10 pages 5 figures Latex, Contribution to DPF '9

Measurement of AcA_c with charmed mesons at SLD

We present a direct measurement of the parity-violation parameter A_c. The measurement is based on 550k Z^0 decays collected by the SLD detector. The mean electron-beam polarization is |P_e| = 73 %. The tagging of c-quark events was performed using two methods: The exclusive reconstruction of D^*+, D^+, and D^0 mesons, and the inclusive P_T spectrum of soft-pions (pi_s) in the decay of D^*+ -> D^0 pi_s^+. The results of these two methods are combined to give A_c = 0.688 +- 0.035(stat.) +- 0.025(sys.) (preliminary).Comment: 12 pages 4 figures Latex. Contributed to EPS99 and to Lepton-Photon9