Chiral extrapolations with small sea quark mass data in two-flavor   lattice QCD
  We present results on the light hadron spectrum and quark mass in two-flavor QCD calculated with small sea quark masses down to $m_{PS}/m_{V}=0.35$. The configurations are generated using the RG improved gauge and tadpole-improved clover quark action at $\beta=1.8$, where $a^{-1} \simeq 1$ GeV. Chiral extrapolations are made using not only polynomials and ChPT in the continuum but also formulae of Wilson chiral perturbation theory (WChPT) including $O(a^2)$ chiral breaking terms. We examine the viability of WChPT and its influence on quark masses. 
CP-PACS Collaboration: Y.Namekawa, S.Aoki, M.Fukugita, K-I.Ishikawa,   N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramash...