Nonrelativistic model of tetraquarks and predictions for their masses from fits to charmed and bottom meson data

TL;DR

This paper develops a nonrelativistic diquark-antidiquark model for tetraquarks, fitting known meson data to predict tetraquark masses, some of which align with experimental candidates like $ ext{Z}_b(10610)$ and $ ext{Z}_b(10650)$.

Contribution

It introduces a comprehensive fit to meson data to predict tetraquark and diquark masses, including new predictions for axial-vector diquarks and tetraquarks.

Findings

Predicted masses for 24 ground-state tetraquarks.

Masses of certain tetraquarks match experimental candidates.

Results largely consistent with other theoretical models.

Abstract

We investigate a nonrelativistic model of tetraquarks, which are assumed to be compact and to consist of diquark-antidiquark pairs. We fit, for the first time, basically all currently known values for the measured masses of 45 mesons, including both charmed and bottom mesons, to the model and predict masses of tetraquarks as well as diquarks. In particular, we find masses of four axial-vector diquarks, i.e., $qc$, $cc$, $qb$, and $bb$, where $q = u,d$, and 24 ground-state tetraquarks, including both heavy-light tetraquarks ($qc\overline{qc}$ and $qb\overline{qb}$) and heavy tetraquarks ($cc\overline{cc}$ and $bb\overline{bb}$). In general, our results for the masses of $qb\overline{qb}$, $cc\overline{cc}$, and $bb\overline{bb}$ are largely comparable with other reported results, whereas our results for the masses of $qc\overline{qc}$ are slightly larger than what has been found earlier. Finally, we identify some of the obtained predictions for masses of tetraquarks with masses of experimental tetraquark candidates, and especially, we find that $\psi(4660)$, $Z_b(10610)$, and $Z_b(10650)$ could be described by the model.