Precision measurements of charm hadron properties at Babar

We present preliminary results on the natural line width, $\mathrm{\Gamma }(D^{\ast +})$, in the transition $D^{\ast }(2010{)}^{+}\to D^0{\pi }^{+}$. The $D^0$ is reconstructed in two decay channels: $D^0\to K^{-}{\pi }^{+}$ and $D^0 \rightarrow K^-\pi^+\pi^-\pi^+$. We use Monte Carlo to simulate our reconstruction resolution in the difference of the reconstructed $D^{\ast +}$ and reconstructed $D^0$ masses. We fit a relativistic P-wave Breit-Wigner form convolved with the measured resolution, together with a background function, to the mass difference distribution. For the decay mode $D^0\to K^{-}{\pi }^{+}$ we obtain $\mathrm{\Gamma }=83.5\pm 1.7\pm 1.2$ keV and $\Delta m = m_{D^{* +}} - m_{D^0} = 145425.5 \pm 0.6 \pm 2.6$ keV, where the quoted errors are statistical and systematic, respectively. For the $D^0\rightarrow K^-\pi^+\pi^-\pi^+$ mode, we do not quote a width measurement at this time, but measure $\mathrm{\Delta }m=m_{D^{\ast +}}-m_{D^0}=145426.5\pm 0.4\pm 2.6$ keV. Additionally, we present preliminary results from the decay mode $\Lambda_c (2880)^+ \rightarrow \Lambda_c^+\pi^+\pi^-$ for the mass, width and quasi-two-body branching ratios of the ${\mathrm{\Lambda }}_c(2880{)}^{+}$ baryon. We measure $m({\mathrm{\Lambda }}_c(2880{)}^{+})-m({\mathrm{\Lambda }}_c(2286{)}^{+})=594.9\pm 0.4\pm 0.3$ MeV and $\mathrm{\Gamma }({\mathrm{\Lambda }}_c(2880{)}^{+})=6.2\pm 1.4\pm 1.5$ MeV, where the errors are statistical and systematic, respectively.