Sigma term and strangeness content of the nucleon

TL;DR

This paper reports on a collaborative effort to determine the nucleon sigma term and strangeness content using SU(3) baryon chiral perturbation theory, lattice QCD data, and various interpolation methods to assess uncertainties.

Contribution

It introduces an extended SU(3) baryon chiral perturbation theory framework and combines it with lattice data and interpolation techniques for precise nucleon property determination.

Findings

Consistent results across multiple lattice spacings and pion masses.

Quantified uncertainties using polynomial and rational interpolations.

Enhanced understanding of quark mass dependence of octet baryons.

Abstract

A status report is given for a joint project of the Budapest-Marseille-Wuppertal collaboration and the Regensburg group to study the quark mass-dependence of octet baryons in SU(3) Baryon XPT. This formulation is expected to extend to larger masses than Heavy-Baryon XPT. Its applicability is tested with 2+1 flavor data which cover three lattice spacings and pion masses down to about 190 MeV, in large volumes. Also polynomial and rational interpolations in M_\pi^2 and M_K^2 are used to assess the uncertainty due to the ansatz. Both frameworks are combined to explore the precision to be expected in a controlled determination of the nucleon sigma term and strangeness content.