We determine the topological susceptibility \chi_t in the topologically-trivial sector generated by lattice simulations of N_f = 2+1 QCD with overlap Dirac fermion, on a 16^3 x 48 lattice with lattice spacing ~ 0.11 fm, for five sea quark masses m_q ranging from m_s/6 to m_s (where m_s is the physical strange quark mass). The \chi_t is extracted from the plateau (at large time separation) of the 2-point and 4-point time-correlation functions of the flavor-singlet pseudoscalar meson \eta', which arises from the finite size effect due to fixed topology. In the small m_q regime, our result of \chi_t agrees with the chiral effective theory. Using the formula \chi_t = \Sigma(m_u^{-1} + m_d^{-1} + m_s^{-1})^{-1} by Leutwyler-Smilga, we obtain the chiral condensate \Sigma^{MSbar}(2 GeV) = [249(4)(2) MeV]^3.
@article{arxiv.0810.0085,
title = {Topological susceptibility in (2+1)-flavor lattice QCD with overlap fermion},
author = {T. W. Chiu and S. Aoki and S. Hashimoto and T. H. Hsieh and T. Kaneko and H. Matsufuru and J. Noaki and T. Onogi and N. Yamada},
journal= {arXiv preprint arXiv:0810.0085},
year = {2010}
}
Comments
7 pages, 3 figures, talk presented at the XXVI International Symposium on Lattice Field Theory, July 14-19, 2008, Williamsburg, Virginia, USA