We have measured the fraction of bb» events in hadronic Z0 decays, Rbb», using the vertex detector system of the Mark II detector at the SLAC Linear Collider. We tag bb» events by requiring the coincidence of three or more tracks with significant impact parameters. This tag is 50% efficient and results in a sample of 85% purity. We find Rbb»=0.251+0.049+0.030, in good agreement with other measurements and the standard model prediction. © 1991 The American Physical Society.

The inclusive production of charmonium mesons in B meson decay has been studied in a 20.3 (Formula presented) data set collected by the BABAR experiment operating at the (Formula presented) resonance. Branching fractions have been measured for the inclusive production of the charmonium mesons (Formula presented) (Formula presented) (Formula presented) and (Formula presented) The branching fractions are also presented as a function of the center-of-mass momentum of the mesons and of the helicity of the (Formula presented) © 2003 The American Physical Society.

Using isolated leptons reconstructed in the Mark II detector to tag bb events, we measure the fraction of bb events in hadronic Z0 decays to be 0.23-0.09+0.11, in good agreement with the standard-model prediction of 0.22. We find (Zbb)=0.43-0.17+0.21 GeV. © 1990 The American Physical Society.

Using an impact-parameter tag to select an enriched sample of Z0bb» events, we have measured the difference between the average charged multiplicity of bb» and all hadronic Z0 decays to be 2.11.8(stat) 0.6(syst) tracks per event. The resulting total (nonleading) charged multiplicity for Z0 bb» events is 23.1(12.0)1.8 0.6 tracks. A comparison of this nonleading multiplicity to hadronic multiplicity data in the range of 10 to 60 GeV supports the hypothesis of flavor-independent hadronic fragmentation, and yields a measurement of the average energy fraction of bottom hadrons in Z0 decays of xEb=0.620.100.04. © 1992 The American Physical Society.

We report the observation of 823±57 B0 and 970±65 B+ decays to doubly charmed final states D̄ (*)D(*)K, where D̄(*) and D(*) are fully reconstructed and K is either a K ± or a K0. We use a sample of 82.3 ±0.9 million B B̄ events collected between 1999 and 2002 with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. The 22 ossible B decays to D̄(*)D(*)K are reconstructed exclusively and the corresponding branching fractions or limits are determined. The branching fractions of the B0 and of the B + to D̄(*)D(*)K are found to be Β(B0→D̄(*)D(*)K) = [4.3±0.3(stat)±0.6(syst)]%, Β(B+→D̄ (*)D(*)K) = [3.5±0.3(stat)±0. 5(syst)]%.A search for decays to orbitally excited Ds states, B→D̄(*)DsJ+(DsJ+→D(*)0K+), is also performed. No statistically significant-contributions from Ds1+(2536) →D*0K+ and DsJ+(2573) →D0K+ to the D̄(*)D (*)0K+ final state are found and we set 90% C.L. limits on their production rates. © 2003 The American Physical Society.

We present a measurement of the branching fraction of the decay B ±→χc0K± sample of 89×106 BB̄ pairs collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. The χc0 meson is reconstructed through its two-body decays toπ+ π- and K+K-. We measure B(B± → χc0K±) ×Β(χ c0→π+π-) = [1.32-027+0.28(stat)±0.26(syst)] × 10-6 and B(B ±→ χc0K±) × B(χc0 →K+K-) = [1.49 -0.34+0.36(stat) ±0.22(syst)] × 10 -6. Using the known values for the χc0 decays branching fractions, we combine these results to obtain Β(B ± →χc0K±) = (2.7±0.7)× 10-4. © 2004 The American Physical Society.

We measure the B0 lifetime τB0 and the B 0-B̄0 oscillation frequency Δmd with a sample of approximately 14000 exclusively reconstructed B 0→D*-ℓ+vℓ signal events, selected from 23 million BB̄ pairs recorded at the Y(45) resonance with the BABAR detector at the Stanford Linear Accelerator Center. The decay position of the other B is determined with the remaining tracks in the event, and its b-quark flavor at the time of decay is determined with a tagging algorithm that exploits the correlation between the flavor of the b quark and the charges of its decay products. The lifetime and oscillation frequencies are measured simultaneously with an unbinned maximum-likelihood fit that uses, for each event, the measured difference in decay times of the two B mesons (Δt), the calculated uncertainty on Δt, the signal and background probabilities, and b-quark tagging information for the other B. The results are τB0=(1.523-0.023+0.024±0.022) ps and Δmd=(0.492±0.018 ±0.013) ps-1. The statistical correlation coefficient between τB0 and Δm d is -0.22. © 2003 The American Physical Society.