Nucleon sigma terms with a variational analysis from Lattice QCD

Abstract

We determine the nucleon-sigma terms from lattice quantum chromodynamics (QCD). We find that the dominant excited state contamination in the nucleon three-point function with a scalar current is due to the transition between the nucleon and a S-wave scattering state of a nucleon and a scalar (sigma) meson. In this proof-of-concept study, we analyze a single Nf=3 ensemble with the unphysically large pion mass Mπ=429 MeV. Excited state contamination is substantially reduced compared to the standard method when employing nucleon-sigma type interpolating operators within a generalized eigenvector analysis. Published by the American Physical Society 2025