Malcolm John

Abstract:

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 226.0±2.5 million BB̄ pairs collected by the BABAR detector, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for both charge-conjugate decays. We present measurements of the corresponding branching fractions and their charge asymmetries that supersede those of previous BABAR analyses. We find the charge asymmetries to be consistent with zero. © 2005 The American Physical Society.

Abstract:

Using a sample of 232×106 Υ(4S)→BB̄ events collected with the BABAR detector at the PEP-II B Factory in 1999-2004, we study B-→D0K*(892)- decays where K*-→KS0π- and D0→K-π+, K-π+π0, K-π+π+π- (non-CP final states); K+K-, π+π- (CP+ eigenstates); KS0π0, KS0, and KS0ω (CP- eigenstates). We measure four observables that are sensitive to the angle γ of the CKM unitarity triangle; the partial-rate charge asymmetries ACP± and the ratios of the B-decay branching fraction in CP± and non-CP decays RCP±: ACP+=-0.08±0.19(stat)±0.08(syst), ACP-=-0.26±0.40(stat)±0.12(syst), RCP+=1.96±0.40(stat) ±0.11(syst), and RCP-=0.65±0.26(stat)±0.08(syst). © 2005 The American Physical Society.

Abstract:

We report the observation of the decay B-→Dπ+π-π0K-, where Dπ+π-π0 indicates a neutral D meson detected in the final state π+π-π0, excluding KS0π0. This doubly Cabibbo-suppressed decay chain can be used to measure the CKM phase γ. Using about 229×106 e+e-→BB̄ events recorded by the BABAR experiment at the PEP-II e+e- storage ring, we measure the branching fraction B(B-→Dπ+π-π0K-)= (5.5±1.0(stat.)±0.7(syst.))×10-6 and the decay rate asymmetry A(B-→Dπ+π-π0K-)=-0.02±0.16(stat.)±0. 03(syst.) for the full decay chain. © 2005 The American Physical Society.

Abstract:

The branching fraction of the τ-→3h-2h+ντ decay (h=π,K) is measured with the BABAR detector to be (8.56±0.05±0.42) ×10-4, where the first error is statistical and the second systematic. The observed structure of this decay is significantly different from the phase space prediction, with the ρ resonance playing a strong role. The decay τ-→f1(1285)π-ντ, with the f1(1285) meson decaying to four charged pions, is observed and the branching fraction is measured to be (3.9±0.7±0.5)×10-4. © 2005 The American Physical Society.