학술논문

Study of B→πlν and B→ρlν decays and determination of
Document Type
article
Source
Physical Review D - Particles, Fields, Gravitation and Cosmology. 83(3)
Subject
Nuclear & Particles Physics
Astronomical and Space Sciences
Atomic
Molecular
Nuclear
Particle and Plasma Physics
Quantum Physics
Atomic
Molecular
Nuclear
Particle and Plasma Physics
Language
Abstract
We present an analysis of exclusive charmless semileptonic B-meson decays based on 377×106 BB̄ pairs recorded with the B A BAR detector at the Υ(4S) resonance. We select four event samples corresponding to the decay modes B0→π-ℓ+ν, B +→π0ℓ+ν, B0→ρ -ℓ+ν, and B+→ρ0ℓ +ν and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B→πℓν samples, and similarly the two B→ρℓν samples, and measure the branching fractions B(B0→π -ℓ+ν)=(1.41±0.05±0.07)×10 -4 and B(B0→ρ-ℓ+ν)=(1. 75±0.15±0.27)×10-4, where the errors are statistical and systematic. We compare the measured distribution in q2, the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the Cabibbo-Kobayashi-Maskawa matrix element |V ub|. Based on the measured partial branching fraction for B→πℓν in the range q2