Malcolm John

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.

Abstract:

We present a Dalitz-plot analysis of charmless B± decays to the final state π±π±π using 210fb-1 of data recorded by the BABAR experiment at s=10.58GeV. We measure the branching fractions B(B±→π±π±π)=(16.2±1.2±0.9) ×10-6 and B(B±→ρ0(770)π±)=(8.8±1. 0±0.6-0.7+0.1)×10-6. Measurements of branching fractions for the quasi-two-body decays B±→ρ0(1450)π±, B±→f0(980)π± and B±→f2(1270)π± are also presented. We observe no charge asymmetries for the above modes, and there is no evidence for the decays B±→χc0π±, B±→f0(1370)π± and B±→σπ±. © 2005 The American Physical Society.