Sigma terms of the baryon octet in $N_\mathrm{f} = 2+1$ QCD with Wilson quarks

TL;DR

This paper calculates the sigma terms of the entire baryon octet in 2+1 flavor QCD using lattice simulations with Wilson quarks, providing preliminary results and methodological insights.

Contribution

It extends the determination of sigma terms beyond the nucleon to all octet baryons using lattice QCD with detailed analysis of excited state contamination.

Findings

Preliminary sigma term values for pion and strange contributions

Comparison with indirect determination methods

Analysis of multi-state fit techniques

Abstract

A lot of progress has been made in the direct determination of nucleon sigma terms. Using similar methods, we consider the sigma terms of the other octet baryons as well. These are determined on CLS gauge field ensembles employing the L\"uscher-Weisz gluon action and the Sheikholeslami-Wohlert fermion action with $N_\mathrm{f} = 2 + 1$. The ensembles have pion masses ranging from ${410}\,\mathrm{MeV}$ down to the physical value and lattice spacings covering a range between ${0.098}\,\mathrm{fm}$ and ${0.039}\,\mathrm{fm}$. We present some preliminary results for the pion and strange sigma terms and compare to indirect determinations. To do so, we discuss multi-state fits to tackle the well-known problem of excited state contamination comparing the ratio and summation methods also including priors.