Scalar mesons and tetraquarks from twisted mass lattice QCD

TL;DR

This study uses twisted mass lattice QCD with 2+1+1 flavors to analyze light scalar mesons, finding that low-lying states are consistent with two-meson states and show no evidence of tightly bound tetraquark states.

Contribution

It introduces a comprehensive lattice QCD analysis with diverse operators to investigate the tetraquark nature of scalar mesons, providing new insights into their structure.

Findings

Low-lying states overlap mainly with two-meson states

No evidence of tightly bound tetraquark states found

Results suggest scalar mesons are not tetraquark dominated

Abstract

We study light scalar mesons with particular focus on the a_0(980) using lattice QCD with 2+1+1 dynamical quark flavors. To investigate the structure of these scalar mesons and to identify, whether a sizeable tetraquark component is present, we use a large set of operators, including diquark-antidiquark, mesonic molecule and two-meson operators. We find that the low-lying states overlap essentially exclusively with two-meson states. This indicates that in the channels investigated no tightly bound four-quark states of either molecular or diquark-antidiquark type exist.