Analysis of the pseudoscalar hidden-charm tetraquark states with the QCD sum rules

TL;DR

This paper investigates the mass spectrum of pseudoscalar hidden-charm tetraquark states using QCD sum rules, considering various diquark configurations, and finds a theoretical mass significantly higher than experimental measurements.

Contribution

It introduces a comprehensive method to analyze pseudoscalar hidden-charm tetraquarks with all color-antitriplet diquarks without explicit P-waves, expanding previous models.

Findings

Lowest mass predicted is 4.56 GeV, higher than experimental value.

All diquark types considered, including strange and non-strange.

Provides a theoretical framework for future tetraquark studies.

Abstract

In this work, we take all the color-antitriplet diquarks, such as the scalar, pseudoscalar, vector, axialvector and tensor diquarks, as the basic constituents to construct the local pseudoscalar four-quark currents without importing the explicit P-waves to implement the negative-parity, and investigate the mass spectroscopy of the pseudoscalar hidden-charm tetraquark states without strange, with strange and with hidden-strange in the framework of the QCD sum rules in a consistent and comprehensive way. We obtain the lowest mass $4.56\pm0.08\,\rm{GeV}$ for the pseudoscalar tetraquark state with the symbolic quark constituents $c\bar{c}u\bar{d}$, which is much larger than the experimental value $4239\pm18{}^{+45}_{-10}\,\rm{MeV}$ extracted by the LHCb collaboration.