Evidence for the η_b(1S) Meson in Radiative Υ(2S) Decay

We have performed a search for the η_b(1S) meson in the radiative decay of the Υ(2S) resonance using a sample of 91.6 × 10^6 Υ(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_γ = 609.3^(+4.6)_(-4.5)(stat)±1.9(syst) MeV, corresponding to an η_b(1S) mass of 9394.2^(+4.8)_(-4.9)(stat) ± 2.0(syst) MeV/c^2. The branching fraction for the decay Υ(2S) → γη_b(1S) is determined to be [3.9 ± 1.1(stat)^(+1.1)_(-0.9)(syst)] × 10^(-4). We find the ratio of branching fractions B[Υ(2S) → γη_b(1S)]/B[Υ(3S) → γη_b(1S)]= 0.82 ± 0.24(stat)^(+0.20)_(-0.19)(syst)

Observation and study of baryonic B decays: B -> D(*) p pbar, D(*) p pbar pi, and D(*) p pbar pi pi

We present a study of ten B-meson decays to a D(*), a proton-antiproton pair, and a system of up to two pions using BaBar's data set of 455x10^6 BBbar pairs. Four of the modes (B0bar -> D0 p anti-p, B0bar -> D*0 p anti-p, B0bar -> D+ p anti-p pi-, B0bar -> D*+ p anti-p pi-) are studied with improved statistics compared to previous measurements; six of the modes (B- -> D0 p anti-p pi-, B- -> D*0 p anti-p pi-, B0bar -> D0 p anti-p pi- pi+, B0bar -> D*0 p anti-p pi- pi+, B- -> D+ p anti-p pi- pi-, B- -> D*+ p anti-p pi- pi-) are first observations. The branching fractions for 3- and 5-body decays are suppressed compared to 4-body decays. Kinematic distributions for 3-body decays show non-overlapping threshold enhancements in m(p anti-p) and m(D(*)0 p) in the Dalitz plots. For 4-body decays, m(p pi-) mass projections show a narrow peak with mass and full width of (1497.4 +- 3.0 +- 0.9) MeV/c2, and (47 +- 12 +- 4) MeV/c2, respectively, where the first (second) errors are statistical (systematic). For 5-body decays, mass projections are similar to phase space expectations. All results are preliminary.Comment: 28 pages, 90 postscript figures, submitted to LP0

Evidence for X(3872) → Ψ (2S)y in B^± → X(3872)K^± Decays and a Study of B → ccyK

In a search for B → ccyK decays with the BABAR detector, where cc includes J/Ψ and Ψ (2S), and K includes K^±, K^0_S , and K^*(892), we find evidence for X(3872) → J/Ψy and X(3872) → Ψ (2S) with 3:6σ and 3:5σ significance, respectively. We measure the product of branching fractions B(B^± → X(3872)K^±)B(X(3872) → J/Ψy)= [2:8 ± 0:8(stat) ± 0:1(syst)]X 10^(-6) and B(B^± → X(3872)K^±) X B(X(3872) → Ψ (2S)y) = [9:5 ± 2:7(stat) ± 0:6(syst)] X 10^(-6)

Measurement of D^0-D̅ ^0 Mixing from a Time-Dependent Amplitude Analysis of D^0→K^+π^-π^0 Decays

We present evidence of D^0-D̅ ^0 mixing using a time-dependent amplitude analysis of the decay D^0→K^+π^-π^0 in a data sample of 384  fb^(-1) collected with the BABAR detector at the PEP-II e^+e^- collider at the Stanford Linear Accelerator Center. Assuming CP conservation, we measure the mixing parameters x_(Kππ)^(0′)=[2.61_(-0.68)^(+0.57)(stat)±0.39(syst)]%, y_(Kππ)^(0′)=[-0.06_(-0.64)^(+0.55)(stat)±0.34(syst)]%. This result is inconsistent with the no-mixing hypothesis with a significance of 3.2 standard deviations. We find no evidence of CP violation in mixing

Evidence for B^+ → [overline K]^(*0)K^(*+)

We present measurements of the branching fraction and fraction of longitudinal polarization for the decay B^+ K^(*0)K^(*+) with a sample of (467±5)×10^6 BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider at the SLAC National Accelerator Laboratory. We obtain the branching fraction B(B^+ K^(*0)K^(*+))=(1.2±0.5±0.1)×10^(-6) with a significance of 3.7 standard deviations including systematic uncertainties. We measure the fraction of longitudinal polarization f_L=0.75_(-0.26)^(+0.16)±0.03. The first error quoted is statistical and the second is systematic

Search for B-meson decays to b_1ρ and b_1K^*

We present a search for decays of B mesons to final states with a b_1 meson and a ρ or K^*(892) meson. The search is based on a data sample consisting of 465 million BB̅ pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0×10^(-6) at the 90% confidence level, including systematic uncertainties

Measurement of D⁰-D̅⁰ mixing using the ratio of lifetimes for the decays D⁰→K⁻π⁺ and K⁺K⁻

We measure the rate of D^0-D̅ ^0 mixing with the observable y_(CP)=(τ_(Kπ)/τ_(KK))-1, where τ_(KK) and τ_(Kπ) are, respectively, the mean lifetimes of CP-even D^0→K^+K^- and CP-mixed D^0→K^-π^+ decays, using a data sample of 384  fb^(-1) collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a sample of D^0 and D̅ ^0 decays where the initial flavor of the decaying meson is not determined, we obtain y_(CP)=[1.12±0.26(stat)±0.22(syst)]%, which excludes the no-mixing hypothesis at 3.3σ, including both statistical and systematic uncertainties. This result is in good agreement with a previous BABAR measurement of y_(CP) obtained from a sample of D^(*+)→D^0π^+ events, where the D^0 decays to K^-π^+, K^+K^-, and π^+π^-, which is disjoint with the untagged D^0 events used here. Combining the two results taking into account statistical and systematic uncertainties, where the systematic uncertainties are assumed to be 100% correlated, we find y_(CP)=[1.16±0.22(stat)±0.18(syst)]%, which excludes the no-mixing hypothesis at 4.1σ

Observation of the baryonic B-decay B̅⁰ → Λ꜀⁺ p̅K⁻π⁺

We report the observation of the baryonic B-decay B^0 → Λ^+_cpK^- π^+, excluding contributions from the decay B^0 → Λ^+_c ΛK^-. Using a data sample of 467 X 10^6 BB pairs collected with the BABAR detector at the PEP-II storage ring at SLAC, the measured branching fraction is (4:33 ± 0:82_(stat) ± 0:33_(syst) ± 1:13Λ^+_c) X 10^(-5). In addition we find evidence for the resonant decay B^0 → ∑_c (2455)^(++) pK^- and determine its branching fraction to be (1:11 ± 0:30_(stat) ± 0:09_(syst) ± 0:29_Λ^+_c) X 10^(-5). The errors are statistical, systematic, and due to the uncertainty in the Λ^+_c branching fraction. For the resonant decay B^0 → Λ^+_c pK^(*0) we obtain an upper limit of 2:42 X 10^(-5_ at 90% confidence level

Measurement of B→K^*(892)γ Branching Fractions and CP and Isospin Asymmetries

We present an analysis of the decays B^0→K^(*0)(892)γ and B^+→K^(*+)(892)γ using a sample of about 383×10^6 BB̅ events collected with the BABAR detector at the PEP-II asymmetric energy B factory. We measure the branching fractions B(B^0→K^(*0)γ)=(4.47±0.10±0.16)×10^(-5) and B(B^+→K^(*+)γ)=(4.22±0.14±0.16)×10^(-5). We constrain the direct CP asymmetry to be -0.033<A(B→K^*γ)<0.028 and the isospin asymmetry to be 0.017<Δ_(0-)<0.116, where the limits are determined by the 90% confidence interval and include both the statistical and systematic uncertainties