We present results of a search for [Formula presented] mixing and a measurement of [Formula presented] , the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays, using [Formula presented] decays from [Formula presented] of data collected near [Formula presented] with the BABAR detector at the PEP-II collider. At the [Formula presented] confidence level, allowing for [Formula presented] violation, we find the mixing parameters [Formula presented] and [Formula presented], and the mixing rate [Formula presented] . In the limit of no mixing, [Formula presented] and the [Formula presented] -violating asymmetry [Formula presented]. © 2003 The American Physical Society.

A largely model-independent measurement of the inclusive electron momentum spectrum and branching fraction for semileptonic decays of B mesons is presented based on data recorded at the [Formula Presented] resonance with the BABAR detector. Backgrounds from secondary charm decays are separated from prompt B decays using charge and angular correlations between the electron from one B meson and a high momentum electron tag from the second B meson. The resulting branching fraction is [Formula Presented] Based on this measurement we determine the Cabibbo-Kobayashi-Maskawa (CKM) matrix element [Formula Presented]. © 2003 The American Physical Society.

We report the results of a CP violation analysis 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. The analysis makes use of 324×106 e+e-→BB̄ events recorded by the BABAR experiment at the PEP-II e+e- storage ring. Analyzing the π+π-π0 Dalitz plot distribution and the B±→Dπ+π- π0K± branching fraction and decay rate asymmetry, we find the following one-standard-deviation constraints on the amplitude ratio and on the weak and strong phases: 0.06

We report measurements of the decays B+K+ and B0K0 using a sample of 231 106 BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center. The branching fractions are measured to be B(B+K+)=(7.5 1.0(stat)0.7(syst)) 10-6 and B(B0K0)=(4.1-1.4+1. 7(stat)±0.4(syst)) 10-6 for invariant mass below 2.85 GeV/c2. © 2006 The American Physical Society.

We present measurements of branching fractions and CP-violating asymmetries for neutral B meson decays to two-body final states of charged pions and kaons based on a sample of about 88 million Y(4S)-->BB decays. From a time-independent fit we measure the charge-averaged branching fractions B(B0-->pi+pi-) = (4.7 +/- 0.6 +/- 0.2) x 10^-6, B(B0-->K+pi-) = (17.9 +/- 0.9 +/- 0.7) x 10^-6, and the direct CP-violating charge asymmetry A(Kpi) = -0.102 +/- 0.050 +/- 0.016; [-0.188,-0.016], where the ranges in square brackets indicate the 90% confidence intervals. From a time-dependent fit we measure the B0-->pi+pi- CP-violating parameters Spipi = 0.02 +/- 0.34 +/- 0.05; [-0.54,+0.58] and Cpipi = -0.30 +/- 0.25 +/- 0.04; [-0.72,+0.12].

Four B + →J/ψpΛ̄ candidates in a data set of (88.9±1.0) X 10 6 Y(4S) decays were observed. The probability of the expected charged B background 0.21±0.14 events, producing ≥4 events was 2.5X10 -4 . The branching fraction is (12 -6 +9 )X10 -6 , where the uncertainty includes both statistical and systematic components.

BABAR is a solenoidal detector optimized for the asymmetric-energy beams at PEP-II and is described in detail. As such, charged particle (track) momenta are measured with a 5-layer double-sided silicon vertex tracker and a 40-layer drift chamber (DCH) inside a 1.5 T superconducting solenoidal magnet. This paper reports on an observation of the decays B ± →π ± π 0 and B ± →K ± π 0 , a measurement of their CP-violating charge asymmetries, and a search for the decay B 0 →π 0 π 0 , using (87.9±1.0)×10 6 BB̄ pairs collected with the BABAR detector.

We search for a charged partner of the X(3872) in the decay B → X - K, X- → J/ψπ-π0, using 234 × 106 BB events collected at the Y(4S) resonance with the BABAR detector at the PEP-II e+e- asymmetric-energy storage ring. The resulting product branching fraction upper limits are B(B 0 → X- K+, X- → J/ψπ-π0) < 5.4 × 10-6 and B(B- → X-K̄0, X- → J/ψπ-π0) < 22 × 10-6 at the 90% confidence level. © 2005 The American Physical Society.