$T_{cc}^{+}$ coupled channel analysis and predictions

Abstract

A coupled channel analysis of the $D^{\ast+}D^0$ and $D^{\ast0}D^+$ system is performed to study the doubly charmed $T_{cc}^+$ state recently discovered by the LHCb collaboration. We use a simple model for the scattering amplitude that allows us to describe well the experimental spectrum, and obtain the $T_{cc}^+$ pole in the coupled channel $T$-matrix. We find that this bound state has a large molecular component. The isospin ($I=0$ or $I=1$) of the state cannot be inferred from the $D^0 D^0 \pi^+$ spectrum alone. Therefore, we use the same formalism to predict other $DD\pi$ spectra. In the case the $T_{cc}^+$ has $I=1$, we also predict the location of the other two members ($T_{cc}^{++}$ and $T_{cc}^0$) of the triplet. Finally, using Heavy-Quark Spin Symmetry, we predict the location of possible heavier $D^\ast D^\ast$ ($I=0$ or $I=1$) partners.