On Lattice Computations of K+ --> pi+ pi0 Decay at m_K =2m_pi
  We use one-loop chiral perturbation theory to compare potential lattice computations of the K+ --> pi+ pi0 decay amplitude at m_K=2m_pi with the experimental value. We find that the combined one-loop effect due to this unphysical pion to kaon mass ratio and typical finite volume effects is still of order minus 20-30%, and appears to dominate the effects from quenching. 
Maarten F.L. Golterman and Ka Chun Leung