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.

We study the decay B 0 → ρ 0 ρ 0 in a sample of about 427 million γ(4S) → BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e + e - collider at SLAC. We find the branching fraction B = (0.84 ± 0.29 ± 0.17) × 10-6 and longitudinal polarization fraction of fL = 0.70 ± 0.14 ± 0.05, where the first uncertainty is statistical, and the second is systematic. The evidence for the B 0 → ρ 0 ρ 0 signal has 3.6σ significance. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S00 L = (0.5± 0.9 ± 0.2) and C00 L = (0.4 ± 0.9 ± 0.2), corresponding to the sine and cosine terms in the time evolution of asymmetry. We study the implication of these results for penguin contributions in B → ρρ decays and for the CKM unitarity angle α.

We perform a time-dependent Dalitz plot analysis of B0 → K0 S π+π- in order to extract the CP violation parameters of f0(980)K0 S and ρ0(770)K0 S and direct CP-asymmetries of Kz.ast;+(892)π-. The results are obtained from a data sample of (383 ± 3) × 106 BB decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The measured values of 2βeff in B0 decays to f0(980)K0S and ρ0(770)K0 S are (89+22-20 ± 5 ±8) and (37+19 -17 ± 5 ±6), respectively, where the first quoted uncertainty is statistical, the second is systematic and the third is Dalitz plot signal model uncertainty. We measure the significance of 2βeff (f0(980)K0S) 6= 0 to be 4.3 σ. In decays to Kz.ast;(892)π we find ACP = -0.18 ± 0.10 ± 0.03 ± 0.03. The measured phase difference between the decay amplitudes of B0 → Kz.ast;+(892)π- and B0 → Kz.ast;-(892)π+ is (-164 ± 24 ± 12 ± 15). All results are preliminary.

We present a measurement of time-dependent CP-violating asymmetries in neutral B meson decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. The data sample consists of 29.7 fb-1 recorded at the γ(4S) resonance and 3.9 fb-1 off resonance. One of the neutral B mesons, which are produced in pairs at the γ(4S), is fully reconstructed in the CP decay modes J/ ψKS0, ψ(2S)KS0, χc1KS0, J/ψK*0 (K*0→KS0π0) and J/ψKL0, or in flavor-eigenstate modes involving D(*)π/p/a1 and J/ψK*0 (K*0→K+π -). The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. A neural netsvork tagging algorithm is used to recover events without a clear lepton or kaon tag. The proper time elapsed between the decays is determined by measuring the distance between the decay vertices. Wrong-tag probabilities, the time-difference resolution function, and the B0-B̄0 oscillation frequency Δmd are measured with a sample of about 6350 fully-reconstructed B0 decays in hadronic flavor-eigenstate modes. A maximum-likelihood fit to this flavor eigenstate sample finds Δmd=0.516±0.016(stat)±0.010(syst) ps -1. The value of the asymmetry amplitude sin 2β is determined from a simultaneous maximum-likelihood fit to the time-difference distribution of the flavor-eigenstate sample and about 642 tagged B0 decays in the CP-eigenstate modes. We find sin 2β=0.59 ±0.14(stat)±0. 05(syst), demonstrating that CP violation exists in the neutral B meson system. We also determine the value of the CP violation parameter |λ|=0. 93±0.09(stat)±0.03(syst), which is consistent with the expectation of |λ|=1 for no direct CP violation. © 2002 The American Physical Society.