Measurements of branching fractions of leptonic and hadronic D s+ meson decays and extraction of the Ds+ meson decay constant

Abstract

We present measurements of absolute branching fractions of hadronic and leptonic Ds+ decays to K -K+π+, K̄0K+, ηπ+, μ+νμ and τ+ντ and report a search for the leptonic Ds+ → e +νe decays. The results are obtained from a data sample of 913 fb-1 collected at or near the Y(4S ) and Y(5S ) resonances with the Belle detector at the KEKB asymmetric-energy e+e- collider. The branching fractions of hadronic decays are measured to be B(Ds+ → K-K+π+) = (5.06 ± 0.15 ± 0.21)%; B(Ds+ → K̄0K+) = (2.95 ± 0.11 ± 0.09)%; B(Ds+ → ηπ+) = (1.82 ± 0.14 ± 0.07)%; where the first and second uncertainties are statistical and systematic, respectively. The branching fractions of leptonic decays are measured to be B(Ds+ → μ+ν μ) = (0.531 ± 0.028 ± 0.020)%; B(Ds+ → τ+ντ) = (5.70 ± 0.21-0.30+0.31)%, which are combined to determine the Ds+ meson decay constant fDs = (255.5 ± 4.2 ± 5.1) MeV: We find no significant signal for Ds+ → e+νe decays and set an upper limit of B(Ds+ → e+νe) < 1.0(0.83) × 10-4 at 95% (90%) confidence level.