We report a study of the processes e+e-→ηγ and e+e-→η′γ at a center-of-mass energy of 10.58 GeV, using a 232fb-1 data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20-5+6ηγ and 50-7+8η′γ events over small backgrounds, and measure the cross sections σ(e+e- →ηγ)=4.5-1.1+1.2±0.3fb and σ(e+e- →η′γ)=5.4±0.8±0.3fb. The corresponding transition form factors at q2=112GeV2 are q2|Fη(q2)|=0.229±0. 030±0.008GeV, and q2|Fη′(q2)|=0.251±0.019±0. 008GeV, respectively. © 2006 The American Physical Society.

Using 385fb-1 of e+e- collisions, we study the amplitudes of the singly Cabibbo-suppressed decay D0→K-K+π0. We measure the strong phase difference between the D̄0 and D0 decays to K*(892)+K- to be -35.5°±1.9°(stat)±2.2°(syst), and their amplitude ratio to be 0.599±0.013(stat)±0.011(syst). We observe contributions from the Kπ and K-K+ scalar and vector amplitudes, and analyze their angular moments. We find no evidence for charged κ, nor for higher spin states. We also perform a partial-wave analysis of the K-K+ system in a limited mass range. © 2007 The American Physical Society.

We report on a study of the decay B̄0→D*+ωπ- with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232×106 BB̄ decays, we measure the branching fraction B(B̄0→D*+ωπ-)=(2.88±0. 21(stat.)±0.31(syst.))×10-3. We study the invariant mass spectrum of the ωπ- system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in τ-→ωπ-ντ. We also measure the polarization of the D*+ as a function of the ωπ- mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*+ to be ΓL/Γ=0.654±0.042(stat.)±0.016(syst.). This is in agreement with the expectations from heavy-quark effective theory and factorization assuming that the decay proceeds as B̄0→ D*+ρ(1450)-, ρ(1450)-→ωπ-. © 2006 The American Physical Society.

We describe searches for B meson decays to the charmless vector-vector final states ωK*, ωρ, ωω, and ω with 233×106 BB̄ pairs produced in e+e- BB̄ annihilation at s=10.58GeV. We also search for the vector-scalar B decay to ωf0. We measure the following branching fractions in units of 10-6: B(B0→ω K*0)=2.4±1.1±0.7(<4.2), B(B+→ωK*+)=0.6- 1.2-0.9+1.4+1.1(<3.4), B(B0→ωρ0)=-0.6±0.7-0.3+0. 8(<1.5), B(B+→ωρ+)=10.6±2.1-1.0+1.6, B(B0→ωω)=1.8-0.9+1.3±0.4(<4.0), B(B0→ω)=0. 1±0.5±0.1(<1.2), and B(B0→ωf0)=0.9±0.4-0.1+0. 2(<1.5). In each case the first error quoted is statistical, the second systematic, and the upper limits are defined at the 90% confidence level. For B+→ωρ+ decays we also measure the longitudinal spin component fL=0.82±0.11±0.02 and the charge asymmetry ACP=0.04±0. 18±0.02. © 2006 The American Physical Society.

We describe searches for decays of B mesons to the charmless final states η′η′K. The data consist of 228×106 BB̄ pairs produced in e+e- annihilation, collected with the BABAR detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are B(B0→η′η′K0)<31×10-6 and B(B+→η′η′K+)<25×10-6. © 2006 The American Physical Society.

We study the processes e+e-→K+K-π+π-γ, K+K-π0π0γ and K+K-K+K-γ, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events, respectively, are selected from 232fb-1 of BABAR data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that the K+K-π+π-γ data can be compared with direct measurements of the e+e-→K+K-π+π- reaction; no direct measurements exist for the e+e-→K+K-π0π0 or e+e-→K+K-K+K- reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from e+e-→ (1020)f0(980) and study its structure near threshold. In the charmonium region, we observe the J/ψ in all three final states and several intermediate states, as well as the ψ(2S) in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) and obtain an upper limit of BY(4260)→ π+π- •ΓeeY<0.4eV at 90% C.L. © 2007 The American Physical Society.

A search for the decay of the τ lepton to five charged and two neutral pions is performed using data collected by the BABAR detector at the PEP-II asymmetric-energy e+e- collider. The analysis uses 232fb-1 of data at center-of-mass energies on or near the Υ(4S) resonance. We observe 10 events with an expected background of 6.5-1.4+2.0 events. In the absence of a signal, we set the limit on the branching ratio B(τ-→3π- 2π+2π0ντ)<3.4×10-6 at the 90% confidence level. This is a significant improvement over the previously established limit. In addition, we search for the decay mode τ-→2ωπ-ντ. We observe 1 event with an expected background of 0.4+1.0-0.4 events and calculate the upper limit B(τ-→2ωπ-ντ)<5.4×10-7 at the 90% confidence level. This is the first upper limit for this mode. © 2006 The American Physical Society.

We study the processes e+e-→2(π+π-)π0γ, 2(π+π-)ηγ, K+K-π+π-π0γ and K+K-π+π- ηγ with the hard photon radiated from the initial state. About 20000, 4300, 5500, and 375 fully reconstructed events, respectively, are selected from 232fb-1 of BABAR data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct e+e- measurements, currently available only for the ηπ+π- and ωπ+π- submodes of the e+e-→2(π+π-)π0 channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from e+e-→ω(782)π+π- and study the ω(1420) and ω(1650) resonances. In the charmonium region, we observe the J/ψ in all these final states and several intermediate states, as well as the ψ(2S) in some modes, and we measure the corresponding branching fractions. © 2007 The American Physical Society.

Branching fraction measurements using B-meson decays to Ks0π+π- are presented. These measurements were obtained by analyzing a data sample of 88.9 × 106 Υ(45) → BB̄ decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. Using a maximum likelihood fit, the following branching fraction results were obtained: B(B0π +π-) = (43.7 ± 3.8 ± 3.4) × 10 -6, B(B0 → K*+π-) (12.9 ± 2.4 ± 1.4) × 10-6, and B(B0 → D-(→Ks0π+π -)π+) = (42.7 ± 2.1 ± 2.2) × 10-6. The CP violating charge asymmetry AK*π for the decay B0 → K*+π- was measured to be AK*π = 0.23 ± 0.18-0.06+0.09. For all these measurements the first error is statistical and the second is systematic.