Scalar strange content of the nucleon from lattice QCD

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 m(s)< N vertical bar(s) over bars vertical bar N > = 48 +/- 10 +/- 15 MeV and, correspondingly, f(s) = m(s)< N vertical bar(s) over bars vertical bar N >/m(N) = 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 f(s) = 0.043 +/- 0.011.