$T_{cc}$ and Hidden Charm Tetraquarks $1^+$ and $0^+$in QCD sum rules and Heavy-Quark Spin Symmetry

TL;DR

This paper uses QCD sum rules to analyze the masses of $T_{cc}$ and hidden charm tetraquarks, showing that mass differences are predicted with high precision, aiding experimental identification of these exotic states.

Contribution

It demonstrates that mass differences between certain tetraquarks can be predicted with less than 10 MeV uncertainty, improving the precision of theoretical mass estimates.

Findings

Mass differences are less than 10 MeV uncertain.

Degeneracy of $1^+$ and $0^+$ tetraquarks in heavy-quark limit.

Mass predictions have about 100 MeV uncertainty individually.

Abstract

In this work, $T_{cc}$ double charm tetraquark and $1^{+}$ and $0^{+}$ hidden charm tetraquarks are studied within the QCD sum rules framework. In the heavy-quark limit, the $1^+$ and $0^+$ tetraquarks are degenerate and the difference in their masses is an $1/m_c$ effect. It is shown that, although the uncertainty in the mass predictions of each of these hadrons is ${\cal O}(100\;\mathrm{MeV})$, when the mass differences are studied, the uncertainty is reduced to less than ${\cal O}(10\;\mathrm{MeV})$. Hence, it is concluded that if one of the exotic hadrons is observed and its mass is used as input, the masses of the other hadrons can be determined with a precision of ${\cal O}(10\;\mathrm{MeV})$ using the QCD sum rules method.