Strange quark condensate in the nucleon in 2 + 1 flavor QCD.

We calculate the "strange quark content of the nucleon," <N|s[over]s|N>, which is important for interpreting the results of some dark matter detection experiments. The method is to evaluate quark-line disconnected correlations on the MILC lattice ensembles, which include the effects of dynamical light and strange quarks. After continuum and chiral extrapolations, the result is <N|s[over]s|N> = 0.69(7){stat}(9){syst}, in the modified minimal subtraction scheme (2 GeV) regularization, or for the renormalization scheme invariant form, m_{s} partial differentialM_{N}/ partial differentialm_{s} = 59(6)(8) MeV.