Exploring doubly-heavy tetraquarks in constituent-quark-model based meson-meson coupled-channels approach

TL;DR

This paper uses a well-established constituent-quark-model coupled-channels approach to predict potential doubly-heavy tetraquark partners of the $T_{cc}^+$ state across various sectors, based on previous successful applications to heavy mesons and baryons.

Contribution

It provides parameter-free predictions of doubly-heavy tetraquarks as partners of the $T_{cc}^+$ using a validated meson-meson coupled-channels framework.

Findings

Predicted existence of $T_{cc}^+$ partners in multiple sectors.

Model parameters constrained from previous heavy hadron studies.

Potential identification of new tetraquark states.

Abstract

The LHCb Collaboration announced in 2021 the discovery of a new tetraquark-like state, named $T_{cc}^+$, with minimum quark content $cc\bar u\bar d$, close to the $D^0D^{*+}$ threshold. This has motivated countless theoretical works trying to identify the dynamics which is responsible of the formation of such state; in particular, the one performed by us in Ref. \cite{Ortega:2022efc}, where a $D^0D^{*+}$ molecular candidate whose mass, width, scattering length and effective ranges are in reasonable agreement with experimental measurements. We explore herein the possibility of having $T_{cc}^+$ partners in all doubly-heavy tetraquark sectors, considering doubly represented light antiquarks $u$, $d$ or $s$, and taking into account all possible spin-parity quantum numbers. The computation is done using a constituent-quark-model based meson-meson coupled-channels framework which has been tested many times in the last fifteen years describing conventional heavy mesons and baryons, their coupling with hadron-hadron thresholds but also in exploring its application to compact multiquark structures. The advantage of using an approach with such a relatively large history is that it allows us to make predictions because all the parameters have already been constrained from our previous works. Then, from this perspective, we present a parameter-free model-dependent prediction of doubly-heavy tetraquarks that may be partners of the discovered $T_{cc}^+$ state.