Measurement of $\mathcal{B}\mathcal{(}{D}^{+}\to {\overline{K}}^{*0}{l}^{+}{\nu }_l)$

Using $13.53\mathrm{f}{\mathrm{b}}^{\mathrm{-}\mathrm{1}}$ of CLEO data, we have measured the ratios of the branching fractions $R_e^{+},R_{\mu }^{+}$ and the combined branching fraction ratio $R_l^{+}$, defined by $R_l^{+}=[\mathcal{B}(D^{+}\to {\overline{K}}^{*0}{l}^{+}{\nu }_l)]/[\mathcal{B}(D^{+}\to K^{-}{\pi }^{+}{\pi }^{+})]$. We find $R_e^{+}=0.74\pm 0.04\pm 0.05$, $R_{\mu }^{+}=0.72\pm 0.10\pm 0.05$, and $R_l^{+}=0.74\pm 0.04\pm 0.05$, where the first and second errors are statistical and systematic, respectively. The known branching fraction $\mathcal{B}(D^{+}\to K^{-}{\pi }^{+}{\pi }^{+})$ leads to $\mathcal{B}(D^{+}\to {\overline{K}}^{*0}{e}^{+}{\nu }_e)=(6.7\pm 0.4\pm 0.5\pm 0.4)\%$, $\mathcal{B}(D^{+}\to {\overline{K}}^{*0}{\mu }^{+}{\nu }_{\mu })=(6.5\pm 0.9\pm 0.5\pm 0.4)\%$, and $\mathcal{B}(D^{+}\to {\overline{K}}^{*0}{l}^{+}{\nu }_l)=(6.7\pm 0.4\pm 0.5\pm 0.4)\%$, where the third error is due to the uncertainty in $\mathcal{B}(D^{+}\to K^{-}{\pi }^{+}{\pi }^{+})$.

Figure 1

The distributions of (a) $K\pi$ mass in the third $\delta m$ bin and (b) $\delta m$ for the $D^{+}\to {\overline{K}}^{*0}{e}^{+}{\nu }_e$ analysis using $8.78\mathrm{f}{\mathrm{b}}^{\mathrm{-}\mathrm{1}}$ data. Points are data. The solid lines are the results of our fits, which include both signal and background, and the shaded areas represent our background estimate.