QCD topology and axion's properties from Wilson twisted mass lattice simulations

TL;DR

This study uses Wilson twisted mass lattice simulations to analyze QCD topological susceptibility and chiral observables across a wide temperature range, providing insights into axion properties and their constraints.

Contribution

It offers new lattice QCD results at physical quark masses for topological susceptibility and axion mass estimates over a broad temperature range.

Findings

Topological susceptibility follows a power-law decay at high temperatures.

Chiral observables adhere to leading order Griffith analyticity.

Axion mass constraints align with previous higher pion mass studies.

Abstract

We present the results on topological susceptibility and chiral observables in $N_f=2+1+1$ QCD for temperature range $120<T<600$ MeV. The lattice simulations are performed with Wilson twisted mass fermions at physical pion, strange and charm masses. In high-$T$ region $T\gtrsim 300$ MeV the chiral observables are shown to follow leading order Griffith analyticity, and the topological susceptibility follows a power-law decay as in the instanton dilute gas models. The measured topological susceptibility is used to estimate the mass of QCD axion. The resulting axion mass constraints are in agreement with our previous studies at higher pion masses.