We present a measurement of the average multiplicity of φ mesons in [Formula Presented] [Formula Presented] and [Formula Presented] meson decays. Using 17.6 [Formula Presented] of data taken at the [Formula Presented] resonance by the BABAR detector at the PEP-II [Formula Presented] storage ring at the Stanford Linear Accelerator Center, we reconstruct φ mesons in the [Formula Presented] decay mode and measure [Formula Presented] This is significantly more precise than any previous measurement. © 2004 The American Physical Society.

We present a measurement of the branching fraction for the decay B -→K0*- using a sample of approximately 86×106 BB̄ pairs collected by the BABAR detector from e+e- collisions near the γ(4S) resonance. The D0 is detected through its decays to K -π+, K-π+π0, and K- π+ π- π+, and the K*- through its decay to KS0π -. We measure the branching fraction to be B(B -→D0K*-) = [6.3±0.7(stat) ±0.5(syst)]×10-4. © 2004 The American Physical Society.

A narrow state, which we label DsJ(2458)+, with a mass 2458.0 ± 1.0 (stat) ± 1.0 (syst) MeV/c2, is observed in the inclusive Ds+ π0γ mass distribution in 91 fb-1 of e+e- annihilation data recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e +e- storage ring. The observed width is consistent with the experimental resolution. The data favor decay through D* s(2112) + π0 rather than through D*sJ(2317) + γ. An analysis of D s+ π0 data accounting for the influence of the DsJ(2458)+ produces a D*sJ(2317) + mass of 2317.3±0.4 (stat)±0.8 (syst) MeV/c 2. © 2004 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.

We have studied the (Formula presented) and (Formula presented) decays using a 20.7 (Formula presented) data set collected with the BABAR detector. We observe a signal of (Formula presented) (Formula presented) events and determine the ratio (Formula presented) to be (Formula presented) The CP-violating charge asymmetries for the (Formula presented) and (Formula presented) decays are determined to be (Formula presented) and (Formula presented). © 2002 The American Physical Society.

We have studied the process e+e -→μ+μ-γ at a center-of-mass energy near the γ(4S) resonance for a μ+μ- invariant mass range near the J/Ψ mass and measured the cross section σ(e+e-→J/Ψ γt →μ +μ-γ). The data set, corresponding to an integrated luminosity of 88.4 fb-1, was collected using the BABAR detector at the SLAC PEP-II collider. From the measured cross section we extract the product Γ(J/Ψ→e+e-)B(J/ Ψ→μ+μ-) = 0.330±0.008±0.007 keV. Using the world averages for B(J/Ψ →μ+μ - and B(J/Ψ→e+e-), we derive the J/Ψ electronic and total widths: Γ(J/Ψ→e+e -) = 5.61 ±0.20 keV and Γ = 94.7 ± 4.4 keV. © 2004 The American Physical Society.