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Abstract:

We report on a search for the rare decay B̄0→D*0γ, which in the standard model is dominated by W-exchange. The analysis is based on a data sample comprising 87.8×106 BB̄ pairs collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. No significant signal is observed, and an upper limit on the branching fraction of 2.5×10-5 at the 90% confidence level is obtained. © 2005 The American Physical Society.

Abstract:

We present an analysis of exclusive charmless semileptonic B-meson decays based on 83×106 BB̄ pairs recorded with the BABAR detector at the Υ(4S) resonance. Using isospin symmetry, we measure branching fractions B(B0→π- +ν)=(1.38±0.10±0.16±0.08)×10-4 and B(B0→ρ- +ν)=(2.14±0.21±0.48±0.28)×10-4, where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q2, the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi- Maskawa (CKM) matrix element |Vub|=(3.82±0.14±0.22±0.11-0. 52+0.88)×10-3 from B→π ν, where the fourth error reflects the uncertainty of the form-factor normalization. © 2005 The American Physical Society.

Abstract:

An array of Multi-anode Photomultiplier Tubes (MaPMT) was evaluated for use in the LHCb Ring Imaging Cherenkov (RICH) detectors using a prototype RICH detector in a charged particle beam. The MaPMT performance was measured with different radiator gases with and without lenses. The performance of the MaPMTs in terms of photon yield and pixel cross-talk is presented. (c) 2005 Elsevier B.V. All rights reserved.

Abstract:

A search for the decay of the τ lepton to seven charged pions and one or zero π0 mesons was performed using the BABAR detector at the PEP-II asymmetric-energy e+e- collider. The analysis uses 232.2fb-1 of data at center-of-mass energies on or near the Υ(4S) resonance. We observe 24 events with an expected background of 21.6±1.3 events. Without evidence for a signal, we calculate an upper limit of B(τ-→4π-3π+(π0) ντ)<3.0×10-7 at 90% confidence level. This is an improvement by nearly an order of magnitude over the previously established limit. In addition, we set upper limits for the exclusive decays τ-→4π-3π+ντ and τ-→4π-3π+π0ντ. © 2005 The American Physical Society.

Abstract:

We report on the search for the rare decays B+→D(*)+KS0 in approximately 226×106 Υ(4S)→BB̄ decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We do not observe any significant signal and we set 90% confidence-level upper limits on the branching fractions, B(B+→D+K0)<0.5×10-5 and B(B+→D*+K0)<0.9×10-5. © 2005 The American Physical Society.