First Observation of the ${\Sigma }_{\mathit{c}}^{*+}$ Baryon and a New Measurement of the ${\Sigma }_{\mathit{c}}^{*+}$ Mass

Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the ${\Sigma }_c^{*+}$ charmed baryon, and an updated measurement of the mass of the ${\Sigma }_c^{+}$ baryon. We find $M\left({\Sigma }_c^{*+}\right)-M\left({\Lambda }_c^{+}\right)=(231.0\pm 1.1\pm 2.0)\mathrm{MeV}$, and $M\left({\Sigma }_c^{+}\right)-M\left({\Lambda }_c^{+}\right)=(166.4\pm 0.2\pm 0.3)\mathrm{MeV}$, where the errors are statistical and systematic, respectively.