The pion-nucleon sigma term with $N_f=2+1$ $\mathcal{O}(a)$-improved Wilson fermions

TL;DR

This study estimates the pion-nucleon sigma term using lattice QCD with $N_f=2+1$ flavors of improved Wilson fermions across multiple lattice spacings and pion masses, providing insights into systematic uncertainties.

Contribution

It introduces a comprehensive analysis of the sigma term with chiral interpolation and systematic error estimation on multiple lattice spacings.

Findings

Chiral interpolation from 130 MeV to 350 MeV pion masses.

Analysis across four lattice spacings to assess lattice artefacts.

Systematic uncertainties related to lattice discretization are estimated.

Abstract

We present an analysis of the pion-nucleon sigma term on the CLS ensembles with $N_f=2+1$ flavors of $\mathcal{O}(a)$-improved Wilson fermions. We perform a chiral interpolation based on ensembles with pion masses ranging from 130 MeV to roughly 350 MeV. The analysis covers four lattice spacings between $a\approx [0.05 \, \rm{fm}\ldots 0.09\, \rm{fm}]$, allowing for an estimate of systematics associated with lattice artefacts.