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

We study finite-volume effects on the masses of the ground-st ate octet baryons using covariant baryon chiral perturbation theory (ChPT) up to next-to-leading or der by analyzing the latest nf = 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 HBChP T, 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 ob serve that for the octet baryon masses, at fixed mπL (≫ 1) finite-volume corrections decrease as mπ approaches its physical value, provided that the strange quark mass is at or close to its physical value, as in m ost LQCD setups.