Low-energy constants in the chiral Lagrangian with baryon octet and decuplet fields from Lattice QCD data on CLS ensembles

TL;DR

This paper analyzes Lattice QCD data on baryon masses using the chiral SU(3) Lagrangian, extracting low-energy constants and physical quantities like the sigma terms, while accounting for discretization effects across multiple ensembles.

Contribution

It introduces a method to determine low-energy constants from diverse Lattice QCD data, including finite-box and discretization effects, with consistent results across different QCD actions.

Findings

Extracted pion-nucleon sigma term: 58.7(1.2) MeV

Determined sizeable strangeness content of the nucleon: -316(76) MeV

Achieved good agreement with empirical data and previous lattice results.

Abstract

We perform an analysis of Lattice QCD data on baryon octet and decuplet masses based on the chiral SU(3) Lagrangian. Low-energy constants (LEC) are adjusted to describe baryon masses from a large set of CLS ensembles, where finite-box and discretization effects are considered. The set is successfully compared against previous Lattice QCD data from ensembles generated with distinct QCD actions by the ETMC, QCDSF-UKQCD and HSC groups. Discretization effects are modelled by the use of action and lattice-scale dependent leading orders LEC, where uniform values are imposed in the limit of vanishing lattice scales. From the CLS data set we extract a pion-nucleon sigma term, $\sigma_{\pi N}= 58.7(1.2)$ MeV, compatible with its empirical value and a sizeable strangeness content of the nucleon with $\sigma_{sN} = -316(76)$ MeV.