Hadronic decays of the heavy-quark-spin molecular partner of $T_{cc}^+$

TL;DR

This paper predicts the decay widths of the heavy-quark-spin partner of T_cc+ as a D*D* molecule, including rescattering effects, and estimates its total width to be around 41 keV.

Contribution

It provides the first detailed calculation of the partial decay widths of T_cc*+ considering rescattering effects within a nonrelativistic effective field theory.

Findings

Rescattering corrections can increase decay widths by up to 40%.

The total width of T_cc*+ is predicted to be approximately 41 keV.

Interference effects between intermediate states are small.

Abstract

Starting from the hypothesis that the $T_{cc}^+$ discovered at LHCb is a $D^{\ast+} D^0/D^{\ast 0}D^+$ hadronic molecule, we consider the partial width of its heavy quark spin partner, the $T_{cc}^{\ast +}$ as a $D^{\ast +} D^{\ast 0}$ shallow bound state, decaying into the $D^{\ast}D\pi$ final states including the contributions of the $D^{\ast} D$ and $D^{\ast} \pi$ final state interaction by using a nonrelativistic effective field theory. Because of the existence of the $T_{cc}^+$ pole, the $I=0$ $D^{\ast} D$ rescattering can give a sizeable correction up to about $40\%$ to the decay widths considering only the tree diagrams, and the $D^{\ast} \pi$ rescattering correction is about $10\%$. The four-body partial widths of the $T_{cc}^{*+}$ into $D D\pi\pi$ are also explicitly calculated, and we find that the interference effect between different intermediate $D^*D\pi$ states is small. The total width of the $T_{cc}^{*+}$ is predicted to be about 41 keV.