Suppressed Decays of $D_s^{+}$ Mesons to Two Pseudoscalar Mesons

Using data collected near the $D_s^{*+}{D}_s^{-}$ peak production energy $E_{\mathrm{cm}}=4170\mathrm{MeV}$ by the CLEO-c detector, we study the decays of $D_s^{+}$ mesons to two pseudoscalar mesons. We report on searches for the singly Cabibbo-suppressed $D_s^{+}$ decay modes $K^{+}\eta$, $K^{+}{\eta }^{\prime }$, ${\pi }^{+}{K}_S^0$, $K^{+}{\pi }^0$, and the isospin-forbidden decay mode $D_s^{+}\to {\pi }^{+}{\pi }^0$. We normalize with respect to the Cabibbo-favored $D_s^{+}$ modes ${\pi }^{+}\eta$, ${\pi }^{+}{\eta }^{\prime }$, and $K^{+}{K}_S^0$, and obtain ratios of branching fractions: $\mathcal{B}(D_s^{+}\to K^{+}\eta )/\mathcal{B}(D_s^{+}\to {\pi }^{+}\eta )=(8.9\pm 1.5\pm 0.4)\%$, $\mathcal{B}(D_s^{+}\to K^{+}{\eta }^{\prime })/\mathcal{B}(D_s^{+}\to {\pi }^{+}{\eta }^{\prime })=(4.2\pm 1.3\pm 0.3)\%$, $\mathcal{B}(D_s^{+}\to {\pi }^{+}{K}_S^0)/\mathcal{B}(D_s^{+}\to K^{+}{K}_S^0)=(8.2\pm 0.9\pm 0.2)\%$, $\mathcal{B}(D_s^{+}\to K^{+}{\pi }^0)/\mathcal{B}(D_s^{+}\to K^{+}{K}_S^0)=(5.5\pm 1.3\pm 0.7)\%$, and $\mathcal{B}(D_s^{+}\to {\pi }^{+}{\pi }^0)/\mathcal{B}(D_s^{+}\to K^{+}{K}_S^0)<4.1\%$ at 90% C.L., where the uncertainties are statistical and systematic, respectively.

Figure 1

$M(D_s)$ distributions for Cabibbo-favored $D_s$ modes from data. The points are the data and the superimposed line is the fit (the dotted line is the fitted background) as described in the text.

Figure 2

$M(D_s)$ distributions for Cabibbo-suppressed $D_s$ modes from data. The points are the data and the superimposed line is the fit (the dotted line is the fitted background) as described in the text. Also shown is the distribution for the isospin-forbidden decay $D_s^{+}\to {\pi }^{+}{\pi }^0$.