Finite-volume effects on octet-baryon masses in covariant baryon chiral perturbation theory

TL;DR

This paper investigates how finite-volume effects influence octet-baryon masses using covariant baryon chiral perturbation theory, comparing results with heavy baryon ChPT and analyzing implications for lattice QCD simulations.

Contribution

It provides a detailed comparison of covariant and heavy baryon ChPT approaches, highlighting differences in virtual decuplet baryon contributions to finite-volume effects.

Findings

Covariant ChPT predicts larger octet baryon contributions to finite-volume effects than HBChPT.

Virtual decuplet baryons have a smaller impact in covariant ChPT due to relativistic effects.

Finite-volume corrections decrease as pion mass approaches physical value at fixed m_pi L.

Abstract

We study finite-volume effects on the masses of the ground-state octet baryons using covariant baryon chiral perturbation theory (ChPT) up to next-to-leading order by analyzing the latest $n_f=2+1$ lattice Quantum ChromoDynamics (LQCD) results from the NPLQCD collaboration. Contributions of virtual decuplet baryons are taken into account using the "consistent" coupling scheme. We compare our results with those obtained from heavy baryon ChPT and show that, although both approaches can describe well the lattice data, the underlying physics is different: In HBChPT, virtual decuplet baryons play a more important role than they do in covariant ChPT. This is because the virtual octet baryon contributions to finite-volume corrections are larger in covariant ChPT than in HBChPT, while the contributions of intermediate decuplet baryons are smaller, because of relativistic effects. We observe that for the octet baryon masses, at fixed $m_\pi L$ ($\gg1$) finite-volume corrections decrease as $m_\pi$ approaches its physical value, provided that the strange quark mass is at or close to its physical value, as in most LQCD setups.