Measurements of the properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math>-meson decays

We present a study of the decay properties of charmed $D$ mesons produced near the peak of the ${\ensuremath{\psi}}^{\ensuremath{'}\ensuremath{'}}(3770)$ resonance in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation. Branching fractions for nine Cabibbo-favored and three Cabibbo-suppressed decay modes are presented along with upper limits on one additional Cabibbo-favored and four additional Cabibbo-suppressed decay modes. A study of $K\ensuremath{\pi}\ensuremath{\pi}$-decay-mode Dalitz plots reveals a large quasi-two-body pseudoscalar-vector component for the ${D}^{0}$ decays and an apparent nonuniform population on the Dalitz plot for the ${D}^{+}$ decay into ${K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$. Using tagged events, we measure the charged-particle multiplicity and strange-particle content of $D$ decays. A measurement of the ${D}^{+}$ and ${D}^{0}$ semileptonic decay fractions indicates that the ${D}^{+}$ has a significantly longer lifetime than the ${D}^{0}$.