Exclusive $D_s$ semileptonic branching fraction measurements

Abstract

We measure absolute branching fractions for six exclusive $D_s$ 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 $\mathcal{B}(D_s\to \varphi e\nu )=(2.14\pm 0.17\pm 0.09)$%, $\mathcal{B}(D_s\to \eta e\nu )=(2.28\pm 0.14\pm 0.20)$%, and $\mathcal{B}(D_s\to {\eta }^{\prime }e\nu )=(0.68\pm 0.15\pm 0.06)$% for the largest modes, where the first uncertainties are statistical and the second are systematic. We also obtain $\mathcal{B}(D_s\to K^{0}e\nu )=(0.39\pm 0.08\pm 0.03)$%, $\mathcal{B}(D_s\to K^{\ast }e\nu )=(0.18\pm 0.04\pm 0.01)$%, and $\mathcal{B}(D_s\to f_{0}e\nu ,f_0\to \pi \pi )=(0.13\pm 0.02\pm 0.01)$% for $f_0$ masses within 60 MeV of 980 MeV. We use our results to determine the $\eta -{\eta }^{\prime }$ and $f_0$ mixing angles with $s\bar{s}$, and we combine our results with lattice calculations to estimate $|V_{cs}|$. This measurement improves upon the $D_s$ semileptonic branching ratio precision and provides a new approach for future work that eliminates the $D_s^{\ast }$ daughter photon reconstruction.

arXiv comment18 pages, 3 figures