New Measurements of Cabibbo-Suppressed Decays of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math>Mesons with the CLEO-c Detector

Abstract

Using $281\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of data collected with the CLEO-c detector, we report on first observations and measurements of Cabibbo-suppressed decays of $D$ mesons in the following six decay modes: ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$, $\ensuremath{\eta}{\ensuremath{\pi}}^{0}$, and $\ensuremath{\omega}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. Improved branching fraction measurements in eight other multipion decay modes are also presented. The measured $D\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}$ rates allow us to extract the ratio of isospin amplitudes $A(\ensuremath{\Delta}I=3/2)/A(\ensuremath{\Delta}I=1/2)=0.420\ifmmode\pm\else\textpm\fi{}0.014(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.016(\mathrm{syst})$ and the strong phase shift of ${\ensuremath{\delta}}_{I}=(86.4\ifmmode\pm\else\textpm\fi{}2.8\ifmmode\pm\else\textpm\fi{}3.3)\ifmmode^\circ\else\textdegree\fi{}$, which is quite large and now more precisely determined.