R Aleksan

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We present a search for the decay B + → τ + ν τ in 88.9 × 10 6 Υ (4S) decays recorded with the BABAR detector at the SLAC B-Factory. A sample of semi-exclusive, semi-leptonic B decays (B − → D 0 ℓ − ¯ ν ℓ X), where X is either a photon, π 0 , or nothing, is used to identify the daughter particles that are associated with the other B meson in each event.(More)
A new type of ring-imaging Cherenkov detector is being used for hadronic particle identification in the BABAR experiment at the SLAC B Factory (PEP-II). This detector is called DIRC, an acronym for Detection of Internally Reflected Cherenkov (Light). This paper will discuss the construction, operation and performance of the BABAR DIRC in detail.
We present a measurement of the time-dependent CP-violating (CPV) asymmetries in B0-->K(0)(S)pi(0) decays based on 124x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In a sample containing 122+/-16 signal decays, we obtain the magnitudes of the direct CPV asymmetry(More)
We present preliminary results of a search for several exclusive c harmless hadronic B decays from electron-positron annihilation data collected by the BABAR detector near the 4S resonance. These include three-body decay modes with nal states h h h and h h 0 , and quasi-two-body decay modes with nal states X 0 h and X 0 K 0 S , where h = or K and X 0 = 0 or(More)
We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully(More)
The BABAR detector, situated at the SLAC PEP-II asymmetric e + e ; collider, has been recording data at energies on and around the (4S) resonance since May 1999. In this paper, we brieey describe the PEP-II B Factory and the BABAR detector. The performance presently achieved by the experiment in the areas of tracking, vertexing, calorimetry and particle(More)
The principles of the DIRC ring imaging Cerenkov technique are brieey explained and its choice for the BABAR detector particle identiication system is motivated. A large scale prototype of the DIRC for the BABAR experiment is then described. Details of the design of this prototype and its test in a hadronic particle beam at the CERN-PS are presented, and(More)
We present the results of a search for the decay B0-->tau+tau- in a data sample of (232+/-3)x10(6) Upsilon(4S)-->BB decays using the BABAR detector. Certain extensions of the standard model predict measurable levels of this otherwise rare decay. We reconstruct fully one neutral B meson and seek evidence for the signal decay in the rest of the event. We find(More)
We report on exclusive decays of B mesons into final states containing charmonium using data collected with the BABAR detector at the PEP-II storage rings. The charmonium states considered here are J/ψ , ψ(2S), and χ c1. Branching fractions for several exclusive final states, a measurement of the decay amplitudes for the B 0 → J/ψ K * decay, and(More)