Measurement of B(Ds -> munu)

Abstract

We present a measurement of the branching fraction $B(D_s^{+}\to {\mu }^{+}{\nu }_{\mu })$ using a 548 fb${}^{-1}$ data sample collected by the Belle experiment at the KEKB $e^{+}{e}^{-}$ collider. The $D_s$ momentum is determined by reconstruction of the system recoiling against $DK\gamma X$ in events of the type $e^{+}{e}^{-}\to D_s^{\ast }DKX,D_s^{\ast }\to D_s\gamma$, where $X$ represents additional pions or photons from fragmentation. The full reconstruction method provides high resolution in the neutrino momentum and thus good background separation, equivalent to that reached by experiments at the tau-charm factories. We obtain the branching fraction $B(D_s^{+}\to {\mu }^{+}{\nu }_{\mu })=(6.44\pm 0.76(\mathrm{stat})\pm 0.57(\mathrm{syst}))\cdot 10^{-3}$, implying a $D_s$ decay constant of $f_{D_s}=(275\pm 16(\mathrm{stat})\pm 12(\mathrm{syst}))$ MeV.

6 pages, 2 figures, replaced by version subm. to Phys. Rev. Lett

References in corpus (1)

• High Precision determination of the pi, K, D and D_s decay constants from lattice QCD

Cited by in corpus (4)

• R-parity violating supersymmetry, B_s mixing, and D_s -> l nu
• Measurements of D and Ds decay constants at CLEO
• Charm and Tau Decays: Review of BaBar and Belle Results
• Theoretical Perspectives: XLIII Rencontres de Moriond - QCD