Nucleon strange quark content in 2+1-flavor QCD

TL;DR

This paper computes the strange quark content of the nucleon in 2+1-flavor QCD using lattice techniques, employing chiral symmetry preservation and advanced propagator methods for accurate results.

Contribution

It provides a direct lattice QCD calculation of the nucleon strange quark content with improved techniques and extrapolation to the physical point, confirming previous estimates.

Findings

Strange quark content f_{T_s} = 0.013(12)(16) at physical point

Results agree with previous indirect calculations and N_f=2 estimates

Employs overlap quark action and low-mode averaging for accuracy.

Abstract

We calculate the strange quark content of the nucleon directly from its disconnected three-point function in N_f=2+1 QCD. Chiral symmetry is crucial to avoid a possibly large contamination due to operator mixing, and is exactly preserved by employing the overlap quark action. We also use the all-to-all quark propagator and the low-mode averaging technique in order to accurately calculate the relevant nucleon correlator. Our preliminary result extrapolated to the physical point is f_{T_s} = 0.013(12)(16). This is in good agreement with our previous estimate in N_f=2 QCD as well as those from our indirect calculations using the Feynman-Hellmann theorem.