Hunting for the strangeness content of the nucleon

TL;DR

This paper investigates the strangeness content of the nucleon and its spin contribution using advanced variance reduction techniques, achieving significant computational efficiency improvements in lattice QCD calculations.

Contribution

The study introduces combined variance reduction methods that significantly enhance the efficiency of calculating disconnected loops in nucleon structure studies.

Findings

Achieved 25-30 times faster computations for disconnected loops.

Found that gauge noise dominates the error in strangeness content calculations.

Provided new insights into the strangeness contribution to nucleon properties.

Abstract

We present results for the strangeness contribution to the nucleon, <N|ss|N>, and to the spin of the nucleon, Delta s. By combining several variance reduction techniques for all-to-all propagators we are able to obtain gains in terms of computer time of factors of 25-30 for the disconnected loop that is needed within the calculation of Delta s, relative to the standard approach of just employing time partitioning/dilution. For <N|ss|n>, the error is dominated by the gauge noise.