Nucleon strangeness form factors from Nf=2+1 clover fermion lattice QCD

We present the Nf=2+1 clover fermion lattice QCD calculation of the nucleon strangeness form factors. We evaluate disconnected insertions using the Z(4) stochastic method, along with unbiased subtractions from the hopping parameter expansion. We find that increasing the number of nucleon sources for each configuration improves the signal significantly. We obtain GMs(0)=-0.017(25)(07) , where the first error is statistical, and the second is the uncertainties in Q2 and chiral extrapolations. This is consistent with experimental values, and has an order of magnitude smaller error.