O(a) improvement of lattice QCD with two flavors of Wilson quarks
  We consider O(a) improvement for two flavor lattice QCD. The improvement term in the action is computed non-perturbatively for a large range of the bare coupling. The position of the critical line and higher order lattice artifacts remaining after improvement are estimated. We also discuss the behavior of the HMC algorithm in our simulations. 
Karl Jansen and Rainer Sommer