Measurement of the absolute branching fractions for D-s(-) --> l(-) (nu)over-bar(l) and extraction of the decay constant f(Ds)

• Main Authors: Cowan, Ray Franklin (Contributor), Dujmic, Denis (Contributor), Sciolla, Gabriella (Contributor), Zhao, M. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2011-06-21T14:13:15Z.
• Subjects: Article
• Online Access: Get fulltext

 The absolute branching fractions for the decays Ds--->ℓ-[nu] ℓ (ℓ=e, mu, or tau) are measured using a data sample corresponding to an integrated luminosity of 521  fb-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-[nu]ℓ 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 fDs=(258.6±6.4±7.5)  MeV, where the first uncertainty is statistical and the second is systematic.