Numerical simulations with two flavours of twisted-mass Wilson quarks   and DBW2 gauge action
  Discretisation errors in two-flavour lattice QCD with Wilson-quarks and DBW2 gauge action are investigated by comparing numerical simulation data at two values of the bare gauge coupling. Both non-zero and zero twisted mass values are considered. The results, including also data from simulations using the Wilson plaquette gauge action, are compared to next-to-leading order chiral perturbation theory formulas. 
F. Farchioni, P. Hofmann, K. Jansen, I. Montvay, G. Muenster, E.E.   Scholz, L. Scorzato, A. Shindler, N. Ukita, C. Urbach, ...