Measurement of the branching fractions for Ψ(2S)→e +e- and Ψ(2S)→μ+-
Physical Review D 65:3 (2002)
Abstract:
We measure the branching fractions of the Ψ(2S) meson to the leptonic final states e+e- and μ+μ- relative to that for Ψ(2S)→J/Ψπ_. The method uses Ψ(2S) mesons produced in the decay of B mesons at the Y(45) resonance in a data sample collected with the BABAR detector at the Stanford Linear Accelerator Center. Using previous measurements for the Ψ(2S) →J/Ψπ+π- branching fraction, we determine the e+e- and π+π- branching fractions to be 0.0078±0.0009±0.0008 and 0.0067±0. 0008±0.0007, respectively. © 2001 The American Physical Society.Properties of hadronic final states in diffractive deep inelastic ep scattering at DESY HERA
Physical Review D 65:5 (2002)
Abstract:
Characteristics of the hadronic final state of diffractive deep inelastic scattering events ep→eXp were studied in the kinematic range 4Study of CP-violating asymmetries in B0→ π+π-K+π- decays
Physical Review D 65:5 (2002)
Abstract:
We present a measurement of the time-dependent CP-violating asymmetries in neutral B decays to the eigenstate, and an updated measurement of the charge asymmetry in B0→K+π-~ decays. In a sample of 33 million Y(4S)→BB̄ decays collected with the BABAR detector at the SLAC PEP-II asymmetric B factory, we find 65-11+12 and 217±18 K+π- candidates and measure the asymmetry parameters Sππ=0.03-0.56+0.53±0.111, Cππ=-0.25-0.17+0.45±0.14, and AKπ = -0.07±0. 08±0.02, where the first error is statistical and the second is systematic. © 2002 The American Physical Society.Study of time-dependent CP-violating asymmetries and flavor oscillations in neutral B decays at the γ (4S)
Physical Review D 66:3 (2002)
Abstract:
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.Exclusive photoproduction of J/ψ mesons at HERA
EUROPEAN PHYSICAL JOURNAL C 24:3 (2002) 345-360