Twisted mass lattice QCD with non-degenerate quark masses
  Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term is considered in the framework of chiral perturbation theory. For two and three numbers of quark flavours, respectively, with non-degenerate quark masses the pseudoscalar meson masses and decay constants are calculated in next-to-leading order including lattice effects quadratic in the lattice spacing a. 
Gernot M\"unster and Tobias Sudmann (University of Muenster)