Measurement of the D-s Decay Constant fDs and Observation of New Charm Resonances Decaying to D*π
- Stanford Univ., CA (United States)
The absolute branching fractions for the decays D-s → ℓ-$$\bar{v}$$-(ℓ = e, μ, or τ) 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 PEPII 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- → DKXD*s-, where D*s- → Ds- γ and X represents additional pions from fragmentation. The Ds- → ℓ-vℓ events are detected by full or partial reconstruction of the recoiling system DKX{gamma}ℓ. The following results are obtained: β(Ds- → μ-v) = (6.02 ± 0.38 ± 0.34) x 10-3, {Beta}(Ds-→ τ-v) = (5.00 ± 0.35 ± 0.49) x 10-2, and B(Ds- → e-ν) < 2.8 x 10-4 at 90% C.L., where the first uncertainty is statistical and the second is systematic. The branching fraction measurements are combined to determine the Ds- decay constant fDs = (258.6 ± 6.4 ± 7.5) MeV. In addition, a study has been performed of the D+π}-, D0π}+, and D*+π- systems in inclusive e+e- → cc interactions in a search for excited D meson states. The dataset used consists of {approx}454 fb-1. The mass spectra for these systems show, for the first time, candidates for the radial excitations of the D0, D*0, and D*+, as well as the L = 2 excited states of the D0 and D-, where L is the orbital angular momentum of the quarks. Finally, a prototype of a next generation Detector of Internally Reflected Cherenkov radiation (Focusing DIRC) has been tested using a 10 GeV electron beam at SLAC. The Focusing DIRC is based on the DIRC which was used in the BABAR detector, but has new pixel photon detectors which improve the resolution on the single photon time of propagation by about an order of magnitude allowing, for the first time, to correct the chromatic smearing in the Cherenkov angle. The Focusing DIRC may be used in a future Super-B factory.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1036487
- Report Number(s):
- SLAC-R-964; TRN: US1201502
- Country of Publication:
- United States
- Language:
- English
Similar Records
Measurement of the Absolute Branching Fractions for $D^-_s\!\rightarrow\!\ell^-\bar{\nu}_{\ell}$ and Extraction of the Decay Constant $f_{D_s}$
Leptonic Decays of the Charged B Meson