We present measurements of the decays B+ -> X(3872) K+ and B0 -> X(3872) K0 with X(3872) -> Jpsi pi+ pi-. The data sample used, collected with the BABAR detector at the PEP-II e+e- asymmetric-energy ...storage ring, corresponds to 455 x 10^6 BBbar pairs. Branching fraction measurements of BF(B+ -> X(3872) K+) x BF(X(3872) -> Jpsi pi+ pi-) = (8.4 +/- 1.5 +/- 0.7) x 10^{-6} and BF(B0 -> X(3872) K0) x BF(X(3872) -> Jpsi pi+ pi- = (3.5 +/- 1.9 +/- 0.4) x 10^{-6} are obtained. We set an upper limit on the natural width of the X(3872) of Gamma < 3.3 MeV/c^2 at the 90% confidence level.
We search for a light Higgs boson A 0 in the radiative decay Υ ( 3 S ) → γ A 0 , A 0 → τ + τ − , τ + → e + ν e ¯ ν τ , or τ + → μ + ν μ ¯ ν τ . The data sample contains 122 × 10 6 Υ ( 3 S ) events ...recorded with the BABAR detector. We find no evidence for a narrow structure in the studied τ + τ − invariant mass region of 4.03 < m τ + τ − < 10.10 GeV / c 2 . We exclude at the 90% confidence level (C.L.) a low-mass Higgs boson decaying to τ + τ − with a product branching fraction B ( Υ ( 3 S ) → γ A 0 ) × B ( A 0 → τ + τ − ) > ( 1.5 - 16 ) × 10 − 5 across the m τ + τ − range. We also set a 90% C.L. upper limit on the τ + τ − decay of the η b at B ( η b → τ + τ − ) < 8 % .
Using the entire sample of 467 × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, we perform an ...analysis of B ± → D K ± decays, using decay modes in which the neutral D meson decays to either C P -eigenstates or non- C P -eigenstates. We measure the partial decay rate charge asymmetries for C P -even and C P -odd D final states to be A C P + = 0.25 ± 0.06 ± 0.02 and A C P − = − 0.09 ± 0.07 ± 0.02 , respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A C P + is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct C P violation. We also measure the ratios of the charged-averaged B partial decay rates in C P and non- C P decays, R C P + = 1.18 ± 0.09 ± 0.05 and R C P − = 1.07 ± 0.08 ± 0.04 . We infer frequentist confidence intervals for the angle γ of the unitarity triangle, for the strong phase difference δ B , and for the amplitude ratio r B , which are related to the B − → D K − decay amplitude by r B e i ( δ B − γ ) = A ( B − → ¯¯¯ D 0 K − ) / A ( B − → D 0 K − ) . Including statistical and systematic uncertainties, we obtain 0.24 < r B < 0.45 ( 0.06 < r B < 0.51 ) and, modulo 180°, 11.3 ° < γ < 22.7 ° or 80.8 ° < γ < 99.2 ° or 157.3 ° < γ < 168.7 ° ( 7.0 ° < γ < 173.0 ° ) at the 68% (95%) confidence level.
Using a data sample corresponding to an integrated luminosity of 342 fb − 1 collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass ...energy near 10.58 GeV, we measure B ( τ − → π − π − π + ν τ ( ex . K 0 S ) ) = ( 8.83 ± 0.01 ± 0.13 ) % , B ( τ − → K − π − π + ν τ ( ex . K 0 S ) ) = ( 0.273 ± 0.002 ± 0.009 ) % , B ( τ − → K − π − K + ν τ ) = ( 0.1346 ± 0.0010 ± 0.0036 ) % , and B ( τ − → K − K − K + ν τ ) = ( 1.58 ± 0.13 ± 0.12 ) × 10 − 5 , where the uncertainties are statistical and systematic, respectively. These include significant improvements over previous measurements and a first measurement of B ( τ − → K − K − K + ν τ ) in which no resonance structure is assumed. We also report a first measurement of B ( τ − → ϕ π − ν τ ) = ( 3.42 ± 0.55 ± 0.25 ) × 10 − 5 , a new measurement of B ( τ − → ϕ K − ν τ ) = ( 3.39 ± 0.20 ± 0.28 ) × 10 − 5 and a first upper limit on B ( τ − → K − K − K + ν τ ( ex . ϕ ) ) .
We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K ± π ∓ π ± . Using a sample of ( 383.2 ± 4.2 ) × 10 6 B ¯¯¯ B pairs collected by the BABAR ...detector, we measure C P -averaged branching fractions and direct C P asymmetries for intermediate resonant and nonresonant contributions. We find evidence for direct C P violation in the decay B ± → ρ 0 ( 770 ) K ± , with a C P -violation parameter A C P = ( + 44 ± 10 ± 4 + 5 − 13 ) % .
We present improved measurements of the branching fraction B , the longitudinal polarization fraction f L , and the direct C P asymmetry A C P in the B meson decay channel B + → ρ + ρ 0 . The data ...sample was collected with the BABAR detector at SLAC. The results are B ( B + → ρ + ρ 0 ) = ( 23.7 ± 1.4 ± 1.4 ) × 10 − 6 , f L = 0.950 ± 0.015 ± 0.006 , and A C P = − 0.054 ± 0.055 ± 0.010 , where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the Cabibbo-Kobayashi-Maskawa phase angle α = arg ( − V t d V ∗ t b / V u d V ∗ u b ) to be ( 92.4 + 6.0 − 6.5 ) ° .
Status and prospects of the BaBar SVT Re, V.; Bruinsma, M.; Curry, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2006, Volume:
560, Issue:
1
Journal Article
Peer reviewed
Open access
The
BaBaR Silicon Vertex Tracker (SVT) has been efficiently operated for five years since the start of data taking in 1999. It has met design requirements and no degradation in its performance has ...been observed thus far. However, because of higher than expected background levels, and anticipated further increases in luminosity and dose rates, we have done a thorough study to assess the viability of operating the SVT until the end of the decade.
We measure the direct CP violation asymmetry, A_CP, in B to X_s gamma and the isospin difference of the asymmetry, Delta A_CP, using 429 fb^-1 of data collected at Upsilon(4S) resonance with the ...BaBar detector at the PEP-II asymmetric-energy e+e- storage rings operating at the SLAC National Accelerator Laboratory. B mesons are reconstructed from 10 charged B final states and 6 neutral B final states. We find A_CP = +(1.7 +- 1.9 +- 1.0)%, which is in agreement with the Standard Model prediction and provides an improvement on the world average. Moreover, we report the first measurement of the difference between A_CP for charged and neutral decay modes, Delta A_CP = +(5.0 +- 3.9 +- 1.5)%. Using the value of Delta A_CP, we also provide 68% and 90% confidence intervals on the imaginary part of the ratio of the Wilson coefficients corresponding to the chromo-magnetic dipole and the electromagnetic dipole transitions.
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