We measure the absolute branching fractions of $D_s$ semileptonic decays where the hadron in the final state is one of $\varphi$, $\eta$, ${\eta }^{\prime }$, $K_S^0$, $K^{\star 0}$, and $f_0$, using $2.8\times {10}^5$ $e^{+}{e}^{-}\to D_s{D}_s^{\star }$ decays collected in the CLEO-c detector at a center-of-mass energy close to 4170 MeV. We obtain $\mathcal{B}(D_s^{+}\to \varphi e^{+}{\nu }_e)=(2.29\pm 0.37\pm 0.11)\%$, $\mathcal{B}(D_s^{+}\to \eta e^{+}{\nu }_e)=(2.48\pm 0.29\pm 0.13)\%$, $\mathcal{B}(D_s^{+}\to {\eta }^{\prime }{e}^{+}{\nu }_e)=(0.91\pm 0.33\pm 0.05)\%$, where the first uncertainties are statistical and the second are systematic. We also obtain $\mathcal{B}(D_s^{+}\to K^0{e}^{+}{\nu }_e)=(0.37\pm 0.10\pm 0.02)\%$, and $\mathcal{B}(D_s^{+}\to K^{\star 0}{e}^{+}{\nu }_e)=(0.18\pm 0.07\pm 0.01)\%$, which are the first measurements of Cabibbo suppressed exclusive $D_s$ semileptonic decays, and, $\mathcal{B}(D_s^{+}\to f_0{e}^{+}{\nu }_e)\times \mathcal{B}(f_0\to {\pi }^{+}{\pi }^{-})=(0.13\pm 0.04\pm 0.01)\%$. This is the first absolute product branching fraction determination for a semileptonic decay including a scalar meson in the final state.

• Received 3 March 2009

DOI:https://doi.org/10.1103/PhysRevD.80.052007