I=2 Pion Scattering Length with the Wilson Fermion
  The calculation of the I=2 pion scattering length in quenched lattice QCD is revisited. The calculation is carried out with the Wilson fermion action employing L\"uscher's finite size scaling method at $\beta=5.9$, 6.1, and 6.3 corresponding to the range of lattice spacing $a\simeq 0.12 - 0.07$ fm. We obtain in the continuum limit $a_0m_\pi = -0.0410(69)$, which is consistent with the prediction of chiral perturbation theory $a_0m_\pi=-0.0444(10)$. 
JLQCD Collaboration: S. Aoki, M. Fukugita, S. Hashimoto, K-I.   Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y. ...