Does A Narrow Tetraquark $cc\bar{u}\bar{d}$ State Exist?

The existence of a shallow or virtual tetraquark state, $cc\bar{u}\bar{d}$, is discussed. Using the putative masses for the doubly charmed baryons ($ccu\mathrm{/}ccd$) from SELEX, the mass of the $cc\bar{u}\bar{d}$ state is estimated to be about $3.9GeV$, only slightly above the $D{D}^{\ast }$ threshold. The experimental signatures for various $cc\bar{u}\bar{d}$ masses are also discussed.