Measurement of CP observables for the decays B±→DCP0K±

Physical Review Letters, 2004

Physical Review D, 2006

We report a measurement of the branching fraction of the decay B 0 → ρ 0 π 0 , using 386 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetricenergy e + e − collider. We detect 51 +14 −13 signal events with a significance of 4.2 standard deviations, including systematic uncertainties, and measure the branching fraction to be B B 0 → ρ 0 π 0 = 3.12 +0.88 −0.82 (stat) ± 0.33(syst) +0.50 −0.68 (model) × 10 −6. We also perform the first measurement of direct CP violating asymmetry in this mode.

Physical Review D, 2005

2012

We present branching fraction and CP asymmetry measurements as well as angular studies of B → φφK decays using 464 × 10 6 BB events collected by the BABAR experiment. The branching fractions are measured in the φφ invariant mass range below the ηc resonance (m φφ < 2.85 GeV). We find B(B + → φφK + ) = (5.6 ± 0.5 ± 0.3) × 10 −6 and B(B 0 → φφK 0 ) = (4.5 ± 0.8 ± 0.3) × 10 −6 , where the first uncertaintiy is statistical and the second systematic. The measured direct CP asymmetries for the B ± decays are ACP = −0.10 ± 0.08 ± 0.02 below the ηc threshold (m φφ < 2.85 GeV) and ACP = 0.09 ± 0.10 ± 0.02 in the ηc resonance region (m φφ in [2.94,3.02] GeV). Angular distributions are consistent with J P = 0 − in the ηc resonance region and favor J P = 0 + below the ηc resonance.

Physical Review D, 2008

We report a study of B ± → D * K ± decays with D * decaying to Dπ 0 or Dγ, using 383 × 10 6 BB pairs collected at the Υ (4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. The D meson decays under study include a non-CP mode (K ± π ∓ ), CP -even modes (K ± K ∓ , π ± π ∓ ) and CP -odd modes (K 0 S π 0 , K 0 S φ, K 0 S ω). We measure ratios (R * CP ± ) of branching fractions of decays to CP eigenmode states and to flavor-specific states as well as CP asymmetries (A * CP ± ). These measurements are sensitive to the unitarity triangle angle γ. We obtain A * CP + = −0.11 ± 0.09 ± 0.01, 4 R * CP + = 1.31±0.13±0.04, and A * CP − = 0.06±0.10±0.02, R * CP − = 1.10±0.12±0.04, where the first error is statistical and the second error is systematic. Translating our results into an alternative parametrization, widely used for related measurements, we obtain x * + = 0.11 ± 0.06 ± 0.02 and x * − = 0.00 ± 0.06 ± 0.02. No significant CP -violating charge asymmetry is found in either the flavor-specific mode D → K ± π ∓ or in B ± → D * π ± decays.

Physical Review D, 2002

We have studied the B ± → J/ψ π ± and B ± → J/ψ K ± decays using a 20.7 fb −1 data set collected with the BABAR detector. We observe a signal of 51 ± 10 B ± → J/ψ π ± events and determine the ratio B(B ± → J/ψ π ± )/B(B ± → J/ψ K ± ) to be [3.91 ± 0.78(stat.) ± 0.19(syst.)]%. The CPviolating charge asymmetries for the B ± → J/ψ π ± and B ± → J/ψ K ± decays are determined to be Aπ = 0.01 ± 0.22(stat.) ± 0.01(syst.) and AK = 0.003 ± 0.030(stat.) ± 0.004(syst.). PACS numbers: 13.25.Hw, 14.40.Nd The decay B ± → J/ψ π ± is both Cabibbo-suppressed and color-suppressed. If the leading-order tree diagram

Physical Review D, 2011

We present measurements of the branching fractions, longitudinal polarization, and direct CP-violation asymmetries for the decays B+ -> rho0 K*+ and B+ -> f0(980) K*+ with a sample of 467+/-5 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider at the SLAC National Accelerator Laboratory. We observe B+ -> rho0 K*+ with a significance of 5.3 sigma and measure the branching fraction Br(B+ -> rho0 K*+) = (4.6+/-1.0+/-0.4) x 10^{-6}, the longitudinal polarization fL = 0.78+/-0.12+/-0.03, and the CP-violation asymmetry ACP = 0.31+/-0.13+/-0.03. We observe B+ -> f0(980) K*+ and measure the branching fraction Br(B+ -> f0(980) K*+) x Br(f0(980) -> pi+pi-) = (4.2+/-0.6+/-0.3) x 10^{-6} and the CP-violation asymmetry ACP = -0.15+/-0.12+/-0.03. The first uncertainty quoted is statistical and the second is systematic.

Physical Review Letters, 2006

Physical Review D, 2006

Physical Review Letters, 2003