Tetraquark states in the quark model

Abstract

We perform systematical investigations of heavy flavor tetraquark systems, including fully heavy $QQ\bar{Q}\bar{Q}$ ($Q=b,c$), doubly heavy $Q{Q}^{(\prime )}\bar{q}\bar{q}$ ($q=u,d$), and singly heavy $Qs\bar{q}\bar{q}$ tetraquark systems, within the framework of quark potential model. We employ the Gaussian expansion method and complex scaling method to solve the four-body Hamiltonian and identify bound and resonant states. We further calculate the root mean square radii to study the spatial configurations of tetraquarks. Our calculations reveal a rich spectrum of tetraquark states exhibiting diverse spatial configurations. In particular, we find good candidates for experimental states $X(6900)$, $X(7200)$, $T_{cc}(3875{)}^{+}$, and $T_{\bar{c}\bar{s}0}^{\ast }(2870)$. The fully charmed tetraquark resonances $X(6900)$ and $X(7200)$ are compact teraquark states, while doubly charmed tetraquark bound state $T_{cc}(3875{)}^{+}$ and charm-strange tetraquark resonance $T_{\bar{c}\bar{s}0}^{\ast }(2870)$ are meson molecules. Additionally, more tetraquark bound and resonant states are predicted and may be searched for in future experiments.

12 pages, 2 figures. Talk given at QCD25 (40th anniversary), 30th June-4th July 2025, Montpellier-FR. Version accepted by Journal of Subatomic Particles and Cosmology

References in corpus (17)

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• Observation of structure in the $J/\psi$-pair mass spectrum
• Observation of an exotic narrow doubly charmed tetraquark
• Study of the doubly charmed tetraquark $T_{cc}^{+}$
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• Doubly heavy tetraquark bound and resonant states
• Fully strange tetraquark resonant states as the cousins of $X(6900)$
• Fully heavy tetraquark resonant states with different flavors
• Fully charmed P-wave tetraquark resonant states in the quark model

Cited by in corpus (1)

• Investigating the internal structure of $X(6900)$ in the $2J/\psi$ decay channel