Virtual decuplet effects on octet baryon masses in covariant baryon chiral perturbation theory

TL;DR

This paper investigates the impact of virtual decuplet baryons on octet baryon masses within covariant baryon chiral perturbation theory, showing small effects on mass dependence but improved finite-volume correction descriptions.

Contribution

It explicitly includes virtual decuplet baryons in covariant baryon ChPT up to N$^3$LO, enhancing finite-volume correction modeling and refining sigma term predictions.

Findings

Virtual decuplet effects are small on mass dependence.

Improved fit to small-volume lattice QCD data.

Sigma terms are only slightly affected by decuplet inclusion.

Abstract

We extend a previous analysis of the lowest-lying octet baryon masses in covariant baryon chiral perturbation theory (ChPT) by explicitly taking into account the contribution of the virtual decuplet baryons. Up to next-to-next-to-next-to-leading order (N$^3$LO), the effects of these heavier degrees of freedom are systematically studied. Their effects on the light-quark mass dependence of the octet baryon masses are shown to be relatively small and can be absorbed by the available low-energy constants up to N$^3$LO. Nevertheless, a better description of the finite-volume corrections of the lattice QCD data can be achieved, particularly those with small $M_\phi L$ ($<4$), which is demonstrated by a careful study of the NPLQCD and QCDSF-UKQCD small-volume data. Finally, we show that the predicted pion- and strangeness-baryon sigma terms are only slightly changed by the inclusion of the virtual decuplet baryons.