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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 mₒ⟨N|ss|N⟩=481015 MeV and, correspondingly, fₒ=mₒ⟨N|ss|N⟩/m₍=0. 0510. 0110. 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 fₒ=0. 0430. 011.
Junnarkar et al. (Wed,) studied this question.