Properties of light scalar mesons from lattice QCD

TL;DR

This paper uses lattice QCD with two sea quark flavors to investigate the spectrum, decay properties, and couplings of light scalar mesons, providing insights into their masses and decay constants.

Contribution

It presents new lattice QCD calculations of scalar meson masses, decay constants, and couplings, clarifying the nature of the $a_0(980)$ and $K^*_0$ states.

Findings

The $a_0$ meson has a mass of 1.01(4) GeV.

Determined the coupling strengths to KK and πη channels.

Computed the leptonic decay constant of the lightest non-singlet scalar meson.

Abstract

Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the spectrum and decay of scalar mesons. We are able to determine the $b_1$ - $a_0$ mass difference and this leads to the conclusion that the lightest non-singlet scalar meson ($a_0$) has a mass of 1.01(4) GeV. We determine from the lattice the coupling strength to KK and $\pi \eta$. We compute the leptonic decay constant of the lightest non-singlet scalar meson. We discuss the impact of these lattice results on the interpretation of the $a_0(980)$ state. We also discuss $K^*_0$ states.