Octet baryon masses and sigma terms in covariant baryon chiral perturbation theory

TL;DR

This study uses covariant baryon chiral perturbation theory to analyze octet baryon masses and sigma terms, accounting for lattice QCD artifacts, and predicts sigma terms with improved accuracy.

Contribution

It provides a comprehensive analysis of octet baryon masses and sigma terms using covariant baryon chiral perturbation theory up to NNLO, including lattice artifact corrections.

Findings

Lattice simulations are consistent with each other.

Finite lattice spacing effects up to O(a^2) are negligible.

Finite volume corrections are significant even for large M_phi L.

Abstract

We report on a recent study of the ground-state octet baryon masses and sigma terms in covariant baryon chiral perturbation theory with the extended-on-mass-shell scheme up to next-to-next-to-next-to-leading order. To take into account lattice QCD artifacts, the finite-volume corrections and finite lattice spacing discretization effects are carefully examined. We performed a simultaneous fit of all the $n_f = 2+1$ lattice octet baryon masses and found that the various lattice simulations are consistent with each other. Although the finite lattice spacing discretization effects up to $\mathcal{O}(a^2)$ can be safely ignored, but the finite volume corrections cannot even for configurations with $M_\phi L>4$. As an application, we predicted the octet baryon sigma terms using the Feynman-Hellmann theorem. In particular, the pion- and strangeness-nucleon sigma terms are found to be $\sigma_{\pi N} = 55(1)(4)$ MeV and $\sigma_{sN} = 27(27)(4)$ MeV, respectively.