Light Scalar Tetraquark Mesons in the QCD Sum Rule

TL;DR

This paper investigates the nature of light scalar mesons as tetraquark states using QCD sum rules, revealing that different flavor structures can mix significantly, affecting their theoretical description.

Contribution

It introduces a method to analyze scalar tetraquark mesons with various flavor structures using QCD sum rules, highlighting the mixing between different configurations.

Findings

Reliable sum rules found for mixed tetraquark currents

Similar results obtained from symmetric and anti-symmetric flavor currents

Large mixing between different flavor structures in tetraquark states

Abstract

We study the lowest-lying scalar mesons in the QCD sum rule by considering them as tetraquark states. We find that there are five independent currents for each state with a certain flavor structure. By forming linear combinations, we find that some mixed currents give reliable QCD sum rules. Among various tetraquark currents, we consider those which are constructed by the diquarks having anti-symmetric and symmetric flavor structures. That the results of the QCD sum rule derived from the two types of currents are similar suggests that the tetraquark states can have a large mixing between different flavor structures.