1,721,320 research outputs found
Measurement of branching fractions and CP-violating charge asymmetries for B-meson decays to D(*)D̅ (*), and implications for the Cabibbo-Kobayashi-Maskawa angle γ
No full text
Measurement of CP observables in B+−−DCPK+− decays and constraints on the CKM angle gamma.
No full textReceived 6 July 2010; published 8 October 2010
Using the entire sample of 467×106 Υ(4S)→BB̅ 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±→DK± decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be ACP+=0.25±0.06±0.02 and ACP-=-0.09±0.07±0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter ACP+ is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct CP violation. We also measure the ratios of the charged-averaged B partial decay rates in CP and non-CP decays, RCP+=1.18±0.09±0.05 and RCP-=1.07±0.08±0.04. We infer frequentist confidence intervals for the angle γ of the unitarity triangle, for the strong phase difference δB, and for the amplitude ratio rB, which are related to the B-→DK- decay amplitude by rBei(δB-γ)=A(B-→D̅ 0K-)/A(B-→D0K-). Including statistical and systematic uncertainties, we obtain 0.24<rB<0.45 (0.06<rB<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
Measurement of CP observables for the decays B±→DCP0K±
No full textWe present a study of the decay B-→D(CP)0K- and its charge conjugate, where D(CP)0 is reconstructed in CP-even, CP-odd, and non-CP flavor eigenstates, based on a sample of 232×106 Υ(4S)→BB̅ decays collected with the BABAR detector at the PEP-II e+e- storage ring. We measure the partial-rate charge asymmetries ACP± and the ratios RCP± of the B→D0K decay branching fractions as measured in CP± and non-CP D0 decays: ACP+=0.35±0.13(stat)±0.04(syst), ACP-=-0.06±0.13(stat)±0.04(syst), RCP+=0.90±0.12(stat)±0.04(syst), and RCP-=0.86±0.10(stat)±0.05(syst)
Measurement of branching fractions and CP and isospin asymmetries for B→K*γ
No full textThe branching fractions of the decays B0→K*0γ and B+→K*+γ are measured using a sample of 88×106BB̅ events collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider. We find B(B0→K*0γ)=[3.92±0.20(stat)±0.24(syst)]×10-5, B(B+→K*+γ)=[3.87±0.28(stat)±0.26(syst)]×10-5. Our measurements also constrain the direct CP asymmetry to be -0.074<A(B→K*γ)<0.049 and the isospin asymmetry to be -0.046<Δ0-<0.146, both at the 90% confidence level
- …
