First measurement of $\Gamma {(D}^{*+})$ and precision measurement of $m_{D^{*+}}-m_{D^0}$

We present the first measurement of the $D^{*+}$ width using 9/fb of $e^{+}{e}^{-}$ data collected near the ${\rm Y}\left(4\mathrm{}\mathrm{S}\right)$ resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the $D^{*+}\to D^0{\pi }^{+}$ decay. We find $\Gamma {(D}^{*+})=96\mathrm{}\pm 4\hspace{0.5em}(\mathrm{statistical})\pm 22\hspace{0.5em}(\mathrm{systematic})\hspace{0.5em}\mathrm{keV}.$ We also measure the energy release in the decay and compute $\Delta m\equiv m_{D^{*+}}-m_{D^0}=145.412\mathrm{}\pm 0.002\hspace{0.5em}\left(\mathrm{statistical}\right)\pm 0.012\hspace{0.5em}\left(\mathrm{systematic}\right)\hspace{0.5em}\mathrm{MeV}/{\mathrm{c}}^2.$