Study of B→πlν and B→ρlν decays and determination of |Vub|
We present an analysis of exclusive charmless semileptonic B -meson decays based on 377 × 10 6 B ¯¯¯ B pairs recorded with the BABAR detector at the Υ ( 4 S ) resonance. We select four event samples corresponding to the decay modes B 0 → π − ℓ + ν , B + → π 0 ℓ + ν , B 0 → ρ − ℓ + ν , and B + → ρ 0...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2010 |
| País: | España |
| Institución: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:2445/131732 |
| Acceso en línea: | https://hdl.handle.net/2445/131732 |
| Access Level: | acceso abierto |
| Palabra clave: | Física de partícules Experiments Particle physics |
| Sumario: | We present an analysis of exclusive charmless semileptonic B -meson decays based on 377 × 10 6 B ¯¯¯ B pairs recorded with the BABAR detector at the Υ ( 4 S ) resonance. We select four event samples corresponding to the decay modes B 0 → π − ℓ + ν , B + → π 0 ℓ + ν , B 0 → ρ − ℓ + ν , and B + → ρ 0 ℓ + ν and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B → π ℓ ν samples, and similarly the two B → ρ ℓ ν samples, and measure the branching fractions B ( B 0 → π − ℓ + ν ) = ( 1.41 ± 0.05 ± 0.07 ) × 10 − 4 and B ( B 0 → ρ − ℓ + ν ) = ( 1.75 ± 0.15 ± 0.27 ) × 10 − 4 , where the errors are statistical and systematic. We compare the measured distribution in q 2 , the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the Cabibbo-Kobayashi-Maskawa matrix element | V u b | . Based on the measured partial branching fraction for B → π ℓ ν in the range q 2 < 12 GeV 2 and the most recent QCD light-cone sum-rule calculations, we obtain | V u b | = ( 3.78 ± 0.13 + 0.55 − 0.40 ) × 10 − 3 , where the errors refer to the experimental and theoretical uncertainties. From a simultaneous fit to the data over the full q 2 range and the FNAL/MILC lattice QCD results, we obtain | V u b | = ( 2.95 ± 0.31 ) × 10 − 3 from B → π ℓ ν , where the error is the combined experimental and theoretical uncertainty. |
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