We present the first 2+1 flavour lattice QCD calculations of pseudoscalar flavour-singlet propagators using improved staggered fermions. We explore the relevant techniques and discuss prospects for the larger scale studies now in progress. The disconnected correlator is shown to have a highly non-Gaussian distribution and reliable estimates of the errors require care.
@article{arxiv.0709.4224,
title = {Methods for Pseudoscalar Flavour-Singlet Mesons with Staggered Fermions},
author = {Eric B. Gregory and Alan C. Irving and Chris M. Richards and Craig McNeile},
journal= {arXiv preprint arXiv:0709.4224},
year = {2008}
}