Search for time-dependent B0s - B0s-bar oscillations using a vertex charge dipole technique

We report a search for B0s - B0s-bar oscillations using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the B0s - B0s-bar oscillation frequency: Delta m_s < 4.9 ps-1 and 7.9 < Delta m_s < 10.3 ps-1 at the 95% confidence level.Comment: 18 pages, 3 figures, replaced by version accepted for publication in Phys.Rev.D; results differ slightly from first versio

Search for time-dependent Bs0-Bs0 oscillations using exclusively reconstructed Ds±s mesons

A search for B0s-B0s oscillations is performed using a sample of 400 000 hadronic Z0 decays collected by the SLAC Large Detector experiment. The B0s candidates are reconstructed in the B0s→D-sX channel with D-s→Ππ-, K*0K-. The B0s production flavor is determined using the large forward-backward asymmetry of polarized Z0→bb 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&lt;1.4 ps-1 and 2.4&lt;Δms &lt;5.3 ps-1 at the 95% confidence level

Measurement of the b quark fragmentation function in Z0 decays

We present a measurement of the b-quark inclusive fragmentation function in Z0 decays using a novel kinematic B-hadron energy reconstruction technique. The measurement was performed using 350,000 hadronic Z0 events recorded in the SLD experiment at SLAC between 1997 and 1998. We compared the sacled B-hadron energy distribution with models of b-quark fragmentation and with several ad hoc functional forms. A number of models and functions are excluded by the data. The average scaled energy of weakly-decaying B hadrons was measured to be = 0.709 +-0.003 (stat) +-0.003 (syst) +-0.002 (model).Comment: 32 pages: latex and 11 figures in eps format (submitted to Physical Review D

Physics results from SLD using the CRID

We review recent Z^0 physics results from SLD that use the Cherenkov Ring Imaging Detector for charged particle identification. The performance of the detector and likelihood method are described briefly. Several hadronization measurements are presented, including identified hadron production in events of different primary flavors, leading hadron production, and new correlation studies sensitive to details of both leading and nonleading hadron production. Identified K^+- have been used in conjunction with precision vertexing to study charmless and doubly charmed B-hadron decays. This combination has also been used to tag b, b-bar, c and c-bar jets, yielding precise measurements of B^0-B^0bar mixing and of the asymmetric couplings A_b and A_c. Identified K^+- and Lambda^0 have been used to tag s and s-bar jets, yielding a measurement of A_s. The clean identified particle samples provided efficiently by the CRID allow the purities of these tags to be measured from the data, an essential ingredient for precision physics.Comment: Talk given at the 3rd Intl. Workshop on Ring Imaging Cherenkov Detectors, November 1998, Ein-Gedi, Israel. 24 pages, 11 embedded figures (sized for 2-up printing

Direct measurement of A(b) and A(c) at the Z0 pole using a lepton tag

The parity violation parameters A(b) and A(c) of the Zb (b) over bar and Zc (c) over bar couplings have been measured directly, using the polar angle dependence of the Z(0)-pole polarized cross sections. Bottom and charmed hadrons were tagged via semileptonic decays. Both the muon and electron identification algorithms take advantage of new multivariate techniques, incorporating for the first time information from the SLD Cerenkov Ring Imaging Detector. Based on the 1993-1995 SLD sample of 150 000 Z(0) decays produced with highly polarized electron beams, we measure A(b) = 0.910 +/- 0.068(stat) +/- 0.037(syst), A(c) = 0.642 +/- 0.110(stat) +/- 0.063(syst)

Improved test of the flavor independence of strong interactions

We present an improved comparison of the strong coupling of the gluon to light (q1=u + d+s), c, and b quarks, determined from multijet rates in flavor-tagged samples of hadronic Z° decays recorded with the SLC Large Detector at the SLAC Linear Collider between 1993 and 1995. Flavor separation among primary q1q̄1, cc̄, and bb̄ final states was made on the basis of the reconstructed mass of long-lived heavy-hadron decay vertices, yielding tags with high purity and low bias against ≥ 3-jet final states. We find: αsc/αsuds =1.036±0.043(stat)-0.045+0.041(syst) -0.018+0.020(theory) and αsb/αsuds=1.004±0.018(stat)-0.031+0.026(syst)-0.029+0.018(theory). ©1998 The American Physical Society