Absolute branching fractions of Cabibbo-suppressed $D\to K\overline{K}$ decays

Using $281{\mathrm{pb}}^{-1}$ of data collected with the CLEO-c detector at the $\psi (3770)$ resonance, we have studied Cabibbo-suppressed decays of $D$ mesons to final states with two kaons. We present results for the absolute branching fractions of the modes $D^0\to K^{+}{K}^{-}$, $D^0\to K_S^0{K}_S^0$, and $D^{+}\to K^{+}{K}_S^0$. We measure $\mathcal{B}(D^0\to K^{+}{K}^{-})=(4.08\pm 0.08\pm 0.09)\times {10}^{-3}$, $\mathcal{B}(D^0\to K_S^0{K}_S^0)=(1.46\pm 0.32\pm 0.09)\times {10}^{-4}$, and $\mathcal{B}(D^{+}\to K^{+}{K}_S^0)=(3.14\pm 0.09\pm 0.08)\times {10}^{-3}$. We also determine the ratio $\mathcal{B}(D^0\to K^{+}{K}^{-})/\mathcal{B}(D^0\to {\pi }^{+}{\pi }^{-})=2.89\pm 0.05\pm 0.06$. For each measurement, the first uncertainty is statistical and the second uncertainty is systematic.

Figure 1

$M_{\mathrm{BC}}$ plots for data, left to right: $D^0\to K^{+}{K}^{-}$ and $D^{+}\to K^{+}{K}_S^0$.

Figure 2

$D^0\to K_S^0{K}_S^0$ plots for data, left to right: $M_{\mathrm{BC}}$ fits for the signal region for $D^0\to K_S^0{K}_S^0$, sideband region 1 for $D^0\to K_S^0{K}_S^0$, and sideband region 2 for $D^0\to K_S^0{K}_S^0$. The sideband regions are shown in Fig. 3.

Figure 3

$(M_{{\pi }^{+}{\pi }^{-}}-M_{K_S^0})$ vs $(M_{{\pi }^{+}{\pi }^{-}}-M_{K_S^0})$ for $D^0\to K_S^0{K}_S^0$ candidates. The region labeled “S” is the signal region, the regions labeled “1” are the sideband 1 region, and the regions labeled “2” are the sideband 2 region.