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Measurement of the absolute branching fractions for Ds-→ℓ -ν̄ℓ and extraction of the decay constant fDs
Document Type
article
Source
Physical Review D - Particles, Fields, Gravitation and Cosmology. 82(9)
Subject
hep-ex
Brain Disorders
Down Syndrome
Intellectual and Developmental Disabilities
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
The absolute branching fractions for the decays Ds-→ℓ -ν̄ℓ (ℓ=e, μ, or τ) are measured using a data sample corresponding to an integrated luminosity of 521fb -1 collected at center-of-mass energies near 10.58 GeV with the BABAR detector at the PEP-II e+e- collider at SLAC. The number of Ds- mesons is determined by reconstructing the recoiling system DKXγ in events of the type e+e-→DKXDs*-, where Ds*-→Ds-γ and X represents additional pions from fragmentation. The Ds-→ℓ-νℓ events are detected by full or partial reconstruction of the recoiling system DKXγℓ. The branching fraction measurements are combined to determine the Ds- decay constant fD s=(258.6±6.4±7.5)MeV, where the first uncertainty is statistical and the second is systematic. © 2010 The American Physical Society.