Nucleon strange quark content from two-flavor lattice QCD with exact chiral symmetry

TL;DR

This study computes the strange quark content of the nucleon using two-flavor lattice QCD with exact chiral symmetry, employing overlap fermions to avoid operator mixing issues, and reports a precise value consistent with previous estimates.

Contribution

First direct lattice QCD calculation of nucleon strange quark content using overlap fermions with exact chiral symmetry to eliminate operator mixing.

Findings

Strange quark content f_{T_s} = 0.032(8)(22).

Results agree with previous indirect estimates.

Utilized all-to-all propagator and low-mode averaging techniques.

Abstract

Strange quark content of the nucleon is calculated in dynamical lattice QCD employing the overlap fermion formulation. For this quantity, exact chiral symmetry guaranteed by the Ginsparg-Wilson relation is crucial to avoid large contamination due to a possible operator mixing with $\bar{u}u+\bar{d}d$. Gauge configurations are generated with two dynamical flavors on a 16^3 x 32 lattice at a lattice spacing a \simeq 0.12fm. We directly calculate the relevant three-point function on the lattice including a disconnected strange quark loop utilizing the techniques of all-to-all quark propagator and low-mode averaging. Our result f_{T_s} = 0.032(8)(22), is in good agreement with our previous indirect estimate using the Feynman-Hellmann theorem.