We measure branching fractions and integrated rate asymmetries for the rare decays B-->K(*)l+l-, where l+l- is either e+e- or micro+micro-, using a sample of 384x10(6) BB events collected with the ...BABAR detector at the PEP-II e+e- collider. We find no evidence for direct CP or lepton-flavor asymmetries. However, for dilepton masses below the J/psi resonance, we find evidence for unexpectedly large isospin asymmetries in both B-->Kl+l- and B-->K*l+l- which differ, respectively, by 3.2sigma and 2.7sigma, including systematic uncertainties, from the standard model expectations.
We present a Dalitz plot analysis of charmless B ± decays to the final state π ± π ± π ∓ using a sample of ( 465 ± 5 ) × 10 6 B ¯¯¯ B pairs collected by the BABAR experiment at √ s = 10.58 GeV . ...We measure the branching fractions B ( B ± → π ± π ± π ∓ ) = ( 15.2 ± 0.6 ± 1.2 ± 0.4 ) × 10 − 6 , B ( B ± → ρ 0 ( 770 ) π ± ) = ( 8.1 ± 0.7 ± 1.2 + 0.4 − 1.1 ) × 10 − 6 , B ( B ± → f 2 ( 1270 ) π ± ) = ( 1.57 ± 0.42 ± 0.16 + 0.53 − 0.19 ) × 10 − 6 , and B ( B ± → π ± π ± π ∓ nonresonant ) = ( 5.3 ± 0.7 ± 0.6 + 1.1 − 0.5 ) × 10 − 6 , where the uncertainties are statistical, systematic, and model-dependent, respectively. Measurements of branching fractions for the modes B ± → ρ 0 ( 1450 ) π ± and B ± → f 0 ( 1370 ) π ± are also presented. We observe no significant direct C P asymmetries for the above modes, and there is no evidence for the decays B ± → f 0 ( 980 ) π ± , B ± → χ c 0 π ± , or B ± → χ c 2 π ± .
The photon spectrum in the inclusive electromagnetic radiative decays of the B meson, B → X s γ plus B → X d γ , is studied using a data sample of ( 382.8 ± 4.2 ) × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays ...collected by the BABAR experiment at SLAC. The spectrum is used to extract the branching fraction B ( B → X s γ ) = ( 3.21 ± 0.33 ) × 10 − 4 for E γ > 1.8 GeV and the direct C P asymmetry A C P ( B → X s + d γ ) = 0.057 ± 0.063 . The effects of detector resolution and Doppler smearing are unfolded to measure the photon energy spectrum in the B meson rest frame.
We study the process e+e- -> pi+pi-pi+pi-gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb^-1 of data collected with the BABAR detector at SLAC, corresponding ...to approximately 260,000 signal events. We use these data to extract the non-radiative sigma(e+e- ->pi+pi-pi+pi-) cross section in the energy range from 0.6 to 4.5 Gev. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
We measure time-integrated CP-violating asymmetries of neutral charmed mesons in the modes D0 --> K(-) K(+) and D0 --> pi(-) pi(+) with the highest precision to date by using D0 --> K(-) pi(+) decays ...to correct detector asymmetries. An analysis of 385.8 fb(-1) of data collected with the BABAR detector yields values of a(CP)(KK)=(0.00+/-0.34(stat)+/-0.13(syst))% and a(CP)(pipi)=(-0.24+/-0.52(stat)+/-0.22(syst))%, which agree with standard model predictions.
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.
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 invisible decays of the Upsilon(1S) meson using a sample of 91.4 x 10(6) Upsilon(3S) mesons collected at the BABAR/PEP-II B factory. We select events containing the decay Upsilon(3S) ...--> pi(+)pi(-)Upsilon(1S) and search for evidence of an undetectable Upsilon(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction B(Upsilon(1S) --> invisible) < 3.0 x 10(-4) 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 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 ) ) .
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