dc.contributor |
Universitat de Barcelona |
dc.contributor.author |
Garra Ticó, Jordi |
dc.contributor.author |
Graugés Pous, Eugeni |
dc.contributor.author |
BABAR Collaboration |
dc.date |
2019-04-08T09:28:25Z |
dc.date |
2019-04-08T09:28:25Z |
dc.date |
2010-02-07 |
dc.date |
2019-04-08T09:28:25Z |
dc.identifier.citation |
1550-7998 |
dc.identifier.citation |
601948 |
dc.identifier.uri |
http://hdl.handle.net/2445/131732 |
dc.format |
45 p. |
dc.format |
application/pdf |
dc.language.iso |
eng |
dc.publisher |
American Physical Society |
dc.relation |
Reproducció del document publicat a: https://doi.org/10.1103/PhysRevD.83.032007 |
dc.relation |
Physical Review D, 2010, vol. 83, num. 3, p. 032007 |
dc.relation |
https://doi.org/10.1103/PhysRevD.83.032007 |
dc.rights |
(c) American Physical Society, 2010 |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Física de partícules |
dc.subject |
Experiments |
dc.subject |
Particle physics |
dc.subject |
Experiments |
dc.title |
Study of B→πlν and B→ρlν decays and determination of |Vub| |
dc.type |
info:eu-repo/semantics/article |
dc.type |
info:eu-repo/semantics/publishedVersion |
dc.description.abstract |
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. |