Evidence of New States Decaying into ${\Xi }_{\mathit{c}}^{*}\pi$

Using $13.7{\mathrm{fb}}^{-1\mathrm{}}$ of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into ${\Xi }_c^{0\prime }{\pi }^{+}$ with the subsequent decay ${\Xi }_c^{0\prime }\to {\Xi }_c^0\gamma$, and its isospin partner decaying into ${\Xi }_c^{+\prime }{\pi }^{-}$ followed by ${\Xi }_c^{+\prime }\to {\Xi }_c^{+}\gamma$. We measure the following mass differences for the two states: $M\left({\Xi }_c^0\gamma {\pi }^{+}\right)-M\left({\Xi }_c^0\right)=318.2\mathrm{}\pm 1.3\pm 2.9\mathrm{MeV}$ and $M\left({\Xi }_c^{+}\gamma {\pi }^{-}\right)-M\left({\Xi }_c^{+}\right)=324.0\mathrm{}\pm 1.3\pm 3.0\mathrm{MeV}$. We interpret these new states as the $J^P={\frac{1}{2}}^{-}$ ${\Xi }_{c1\mathrm{}}$ particles, the charmed-strange analogs of the ${\Lambda }_{c1\mathrm{}}^{+}\left(2593\right)$.