SU(2) and SU(3) chiral perturbation theory analyses on baryon masses in 2+1 flavor lattice QCD

TL;DR

This study analyzes baryon masses in 2+1 flavor lattice QCD using SU(3) and SU(2) chiral perturbation theories, revealing limitations of SU(3) expansion and the importance of higher order terms near the physical point.

Contribution

It provides a detailed comparison of SU(3) and SU(2) chiral perturbation theories in describing baryon mass dependence on quark masses in lattice QCD.

Findings

SU(3) chiral expansion fails with phenomenological couplings.

Higher order terms are significant only near the physical point.

Finite size effects are minimal, around 1%.

Abstract

We investigate the quark mass dependence of baryon masses in 2+1 flavor lattice QCD using SU(3) heavy baryon chiral perturbation theory up to one-loop order. The baryon mass data used for the analyses are obtained for the degenerate up-down quark mass of 3 MeV to 24 MeV and two choices of the strange quark mass around the physical value. We find that the SU(3) chiral expansion fails to describe both the octet and the decuplet baryon data if phenomenological values are employed for the meson-baryon couplings. The SU(2) case is also examined for the nucleon. We observe that higher order terms are controlled only around the physical point. We also evaluate finite size effects using SU(3) heavy baryon chiralperturbation theory, finding small values of order 1% even at the physical point.