Malcolm John

Abstract:

We analyze the three-body charmless decay B±→K±K± K using a sample of 226.0±2.5 million BB̄ pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B=(35.2±0.9±1.6)×10-6 and ACP=(-1.7±2.6±1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-)<2GeV/c2. Significant production of the f0(980) resonance, and of a spin zero state near 1.55GeV/c2 are required in the isobar model description of the data. The partial-wave analysis supports this observation. © 2006 The American Physical Society.

Abstract:

We report two novel determinations of |Vub| with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Υ(4S)→BB̄ events. In one approach, we combine the inclusive B̄→Xuν̄ rate, integrated up to a maximum hadronic mass mX<1.67GeV/c2, with a measurement of the inclusive B→Xsγ photon energy spectrum. We obtain |Vub|=(4.43±0.38stat±0.25syst±0.29theo)×10-3. In another approach we measure the total B̄→Xuν̄ rate over the full phase space and find |Vub|=(3.84±0.70stat±0.30syst±0.10theo)×10-3. © 2006 The American Physical Society.

Abstract:

We present a study of the decays B̄0→D(*)0K̄(*)0 using a sample of 226×106 Υ(4S)→BB̄ decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We report evidence for the decay of B0 and B̄0 mesons to the D*0KS0 final state with an average branching fraction B(B∼0→D*0K∼0) ≡(B(B̄0→D*0K̄0)+B(B0→D*0K0))/2=(3. 6±1.2±0.3)×10-5. Similarly, we measure B(B∼0→ D0K∼0)≡(B(B̄0→D0K̄0)+B(B0→D0K0))/2=(5.3±0. 7±0.3)×10-5 for the D0KS0 final state. We measure B(B̄0→D0K̄*0)=(4.0±0.7±0.3)×10-5 and set a 90% confidence level upper limit B(B̄0→D̄0K̄*0) <1.1×10-5. We determine the upper limit for the decay amplitude ratio |A(B̄0→D̄0K̄*0)/A(B̄0→D0K̄*0)| to be less than 0.4 at the 90% confidence level. © 2006 The American Physical Society.