Scalar tetraquark state candidates: $X(3915)$, $X(4500)$ and $X(4700)$

TL;DR

This paper uses QCD sum rules to analyze the masses and structures of certain exotic tetraquark candidates, proposing specific assignments for the states $X(3915)$, $X(4500)$, and $X(4700)$ based on their quark configurations.

Contribution

It is the first detailed QCD sum rule study assigning these states as specific tetraquark configurations with calculated mass spectra.

Findings

Supports $X(3915)$ as ground state axialvector-diquark-axialvector-antidiquark tetraquark.

Identifies $X(4500)$ as the first radial excitation of the same tetraquark type.

Assigns $X(4700)$ as a vector-diquark-vector-antidiquark scalar tetraquark.

Abstract

In this article, we tentatively assign the $X(3915)$ and $X(4500)$ to be the ground state and the first radial excited state of the axialvector-diquark-axialvector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark states, respectively, assign the $X(4700)$ to be the ground state vector-diquark-vector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark state, and study their masses and pole residues with the QCD sum rules in details by calculating the contributions of the vacuum condensates up to dimension 10. The numerical results support assigning the $X(3915)$ and $X(4500)$ to be the ground state and the first radial excited state of the axialvector-diquark-axialvector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark states, respectively, and assigning the $X(4700)$ to be the ground state vector-diquark-vector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark state.