$0^{+}$ fully-charmed tetraquark states

TL;DR

This paper investigates the nature of broad structures observed in J/ψ pair spectra by studying possible $0^{+}$ fully-charmed tetraquark states using QCD sum rules, providing theoretical support for their tetraquark interpretation.

Contribution

The study develops new calculation techniques for four-heavy-quark systems and applies QCD sum rules to identify $0^{+}$ fully-charmed tetraquark states consistent with experimental data.

Findings

Mass predictions align with observed structures

Supports tetraquark interpretation of broad J/ψ pair structures

Develops methods for analyzing four-heavy-quark systems

Abstract

Motivated by the LHCb's new observation of structures in the $J/\psi$-pair invariant mass spectrum, for which could be classified as possible $cc\bar{c}\bar{c}$ tetraquark candidates, we systematically study $0^{+}$ fully-charmed tetraquark states through QCD sum rules. Making the development of calculation techniques to fourfold heavy hadronic systems, four different configuration currents with $0^{+}$ are considered and vacuum condensates up to dimension $6$ are included in the operator product expansion (OPE). Finally, mass values acquired for $0^{+}$ $cc\bar{c}\bar{c}$ tetraquark states agree well with the experimental data of the broad structure, which supports that it could be a $0^{+}$ fully-charmed tetraquark state.