We study the flavour singlet mesons from first principles using lattice QCD. We explore the splitting between flavour singlet and non-singlet for vector and axial mesons as well as the more commonly studied cases of the scalar and pseudoscalar mesons.
@article{arxiv.hep-lat/0107003,
title = {The flavour singlet mesons in QCD},
author = {UKQCD Collaboration and C. McNeile and C. Michael and K. J. Sharkey},
journal= {arXiv preprint arXiv:hep-lat/0107003},
year = {2008}
}