We study the strangeness electromagnetic form factors of the nucleon from the Nf = 2 + 1 clover fermion lattice QCD calculation. The disconnected insertions are evaluated using the Z(4) stochastic method, along with unbiased subtractions from the hopping parameter expansion. In addition to increasing the number of Z(4) noises, 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), 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. We also study the strangeness second moment of the partion distribution function of the nucleon, hx2is s.
|Journal||Proceedings of Science|
|State||Published - 2009|
|Event||27th International Symposium on Lattice Field Theory, LAT 2009 - Beijing, China|
Duration: Jul 26 2009 → Jul 31 2009
Bibliographical noteFunding Information:
We thank the CP-PACS/JLQCD Collaborations for their configurations. This work was supported in part by U.S. DOE grant DE-FG05-84ER40154 and Grant-in-Aid for JSPS Fellows 21·5985. Research of N.M. is supported by Ramanujan Fellowship. The calculation was performed at Jefferson Lab, Fermilab and the Univ. of Kentucky, partly using the Chroma Library .
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