Decays of charmed hadrons at belle

Using e⁺e^- annihilation data recorded by the Belle detector, we obtain preliminary branching fraction B(D⁺_s → μ ⁺ν_μ) (6.44 ± 0.76 ± 0.52) · 10^-3, implying a D⁺_s decay constant of fD_s 275 ± 16 ± 12 MeV. The D⁺_s is tagged in the events e⁺e^- → D^∗+_sDKX, D^∗+_s → D⁺_sγ, by full reconstruction of the DKXγ system, where X denotes additional pions or photon from fragmentation. We observe for the first time the decay D_s1(2536)⁺ → K⁺ with the ratio of branching fractions B(D_s1⁺ → D⁺ π^- K⁺/B(D_s1⁺ → D^∗+K⁰) (3.27 ± 0.18 ± 0.37)%. We also study the angular distributions in the D_s1(2536)⁺ → D^∗+K⁰_s decay and measure the ratio of D- and S-wave amplitudes. The S-wave dominates, with a partial width of Γs/Γtotal 0.72 ± 0.05 ± 0.01.