We present a measurement of time-dependent CP asymmetries and an updated determination of the CP-odd fraction in the decay B 0 → D * + D * −. The measurements are derived from a data sample of 88 × 10 6 B ¯ B pairs collected by the BABAR detector at the PEP-II energy asymmetric B Factory at SLAC. All results are preliminary.
A search for the exclusive radiative decays B → ρ(770)γ and B 0 → ω(782)γ is performed on a sample of 84 million BB events collected by the BABAR detector at the P EP − II asymmetric e + e − collider. No significant signal is seen in any of the channels. We set preliminary upper limits of B[B 0 → ρ 0 γ] < 1.4 × 10 −6 , B[B + → ρ + γ] < 2.3 × 10 −6 and B[B 0… (More)
The D 0 mixing parameter y = ∆Γ/2Γ was determined by measuring the D 0 lifetime separately for the K − π + decay mode and the K − K + decay mode with 12.4 fb −1 of data collected by the BABAR experiment in 2001. Backgrounds were suppressed with the D * → D 0 π + decay and particle identification. The following preliminary result was obtained: y = (−1.0 ±… (More)
_ _ Detector backgrounds at the Stanford Linear Collider are discussed with emphasis on their sources, and methods of controlling them.
The determination of the centre-of-mass energies from the LEP1 data for 1993, 1994 and 1995 is presented. Accurate knowledge of these energies is crucial in the measurement of the Z resonance parameters. The improved understanding of the LEP energy behaviour accumulated during the 1995 energy scan is detailed, while the 1993 and 1994 measurements are… (More)
A lower limit is set on the B 0 s meson oscillation parameter m s using data collected from 1991 to 1994 by the ALEPH detector. Events with a high transverse momentum lepton and a reconstructed secondary vertex are used. The high transverse momentum leptons are produced mainly by b hadron decays, and the sign of the lepton indicates the… (More)
From approximately 3 million hadronic decays of Z bosons recorded with the aleph detector at lep, a sample of 410 32 B 0 ! D + ` ? ` candidates is selected, wherè is either an electron or a muon. The diierential decay rate d?(B 0 ! D + ` ? `)=d! from this sample is tted, yielding a value for the product of the CKM matrix element jV cb j and the… (More)
The SLC linac must produce stable high energy, low emittance beams to make maximum luminosity. The incoming beam conditions must be correct and stable. The trajectories of the two beams must be controlled to about 100 pm. The energy and energy spectrum of each beam are controlled to a few parts per thousand. The beam transverse dimensions are measured to be… (More)
Using about 23M BB events collected in 1999-2000 with the BABAR detector, we report the observation of several hundred B → D (*) D (*) K decays with two completely reconstructed D mesons. The preliminary branching fractions of the low background decay modes B 0 → D * − D (*)0 K + are determined to be B(B 0 → D * − D 0 K +) = (2.8 ± 0.7 ± 0.5) × 10 −3 and… (More)