Insights into the Nucleon Spin from Lattice QCD
  Flavour singlet contributions to the nucleon spin are elusive due to the fact that they cannot be determined directly in experiment but require extrapolations to the small x region. Direct calculations of these contributions are possible using Lattice QCD, however, they pose a significant computational challenge due to the presence of disconnected quark line diagrams. We report on recent progress in determining these sea quark contributions on the lattice. 
Sara Collins (for the QCDSF Collaboration)
hep-lat hep-ph