Scalar mesons and tetraquarks by means of lattice QCD

TL;DR

This paper investigates the internal structure of light scalar mesons a_0(980) and kappa using lattice QCD with multiple operator types to identify potential tetraquark components.

Contribution

It introduces a comprehensive lattice QCD approach with various operators and discusses the inclusion of disconnected diagrams to study scalar mesons' structure.

Findings

Use of diverse operators to probe meson structure

Inclusion of disconnected diagrams for detailed analysis

Framework applicable to other scalar mesons like f_0(980)

Abstract

We study the light scalar mesons a_0(980) and kappa using N_f = 2+1+1 flavor lattice QCD. In order to probe the internal structure of these scalar mesons, and in particular 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. The inclusion of disconnected diagrams, which are technically rather challenging, but which would allow us to extend our work to e.g. the f_0(980) meson, is introduced and discussed.