Nucleon strangeness form factors and moments of PDF

Abstract

The calculation of the nucleon strangeness form factors from Nf = 2 + 1 clover fermion lattice QCD is presented.
Disconnected insertions are evaluated 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 Gs
M(0) = −0.017(25)(07), which is consistent with experimental values, and has an order of
magnitude smaller error. Preliminary results for the strangeness contribution to the second moment of the parton distribution
function are also presented.