Discovery of the doubly charmed $T_{cc}^{+}$ state implies a triply charmed $H_{ccc}$ hexaquark state

Abstract

The doubly charmed exotic state $T_{cc}$ recently discovered by the LHCb Collaboration could well be a $D{D}^{\ast }$ molecular state long predicted in various theoretical models, in particular, the $D{D}^{\ast }$ isoscalar axial vector molecular state predicted in the one-boson-exchange model. In this work, we study the $DD{D}^{\ast }$ system in the Gaussian Expansion Method with the $D{D}^{\ast }$ interaction derived from the one-boson-exchange model and constrained by the precise binding energy of $273\pm 63$ keV of $T_{cc}$ with respect to the $D^{\ast +}{D}^0$ threshold. We show the existence of a $DD{D}^{\ast }$ state with a binding energy of a few hundred keV and spin-parity $1^{-}$. Its main decay modes are $DDD\pi$ and $DDD\gamma$. The existence of such a state could in principle be confirmed with the upcoming LHC data and will unambiguously determine the nature of the $T_{cc}^{+}$ state and of the many exotic state of similar kind, thus deepening our understanding of the non-perturbative strong interaction.

Comments: 4 pages, 3 figures