2013/01/31 by Parikshit Junnarkar, Andre Walker-Loud · 1 citation
Physics and Astronomy · #hep-lat #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevd.87.114510
20 pages, 19 figures: v2. improved discussion of scale setting, Matrix-Prony method and lattice average. Updated references. Version accepted for publication in PRD: v3, improved figure 5
arxiv created 2013/06/25 · arxiv updated 2013/06/26
The scalar strange-quark matrix element of the nucleon is computed with lattice QCD. A mixed-action scheme is used with domain-wall valence fermions computed on the staggered MILC sea-quark configurations. The matrix element is determined by making use of the Feynman-Hellmann theorem which relates this strange matrix element to the change in the nucleon mass with respect to the strange-quark mass. The final result of this calculation is ms < N | s-bar s| N > = 49 +-10 +- 15 MeV and, correspondingly fs = ms < N | s-bar s |N > / mN = 0.051 +- 0.011 +- 0.016. Given the lack of a quantitative comparison of this phenomenologically important quantity determined from various lattice QCD calculations, we take the opportunity to present such an average. The resulting conservative determination is fs = 0.043 +- 0.011.