Exclusive Ds semileptonic branching fraction measurements

We measure absolute branching fractions for six exclusive Ds semileptonic decays. We use data collected in the CLEO-c detector from e+e- annihilations delivered by the Cornell Electron Storage Ring with a center-of-mass energy near 4170 MeV. We find B(Ds→φeν)=(2.14±0.17±0.08)%, B(Ds→ηeν)=(2.28±0.14±0.19)%, and B(Ds→η′eν)=(0.68±0.15±0.06)% for the largest modes, where the first uncertainties are statistical and the second are systematic. We also obtain B(Ds→K0eν)=(0.39±0.08±0.03)%, B(Ds→K∗eν)=(0.18±0.04±0.01)%, and B(Ds→f0eν,f0→ππ)=(0.13±0.03±0.01)% for f0 masses within 60 MeV of 980 MeV. We use our results to determine the η-η′ and f0 mixing angles with ss¯, and we combine our results with lattice calculations to estimate |Vcs|. This measurement improves upon the Ds semileptonic branching ratio precision and provides a new approach for future work that eliminates the Ds∗ daughter photon reconstruction.