Lattice artefacts in SU(3) lattice gauge theory with a mixed fundamental and adjoint plaquette action

We investigated SU(3) lattice gauge theory with a fundamental and adjoint plaquette term in the action. The purpose is to test whether the choice of a negative adjoint coupling can reduce lattice artefacts and improve the scaling b ehaviour. To this end, we have studied the finite temperature phase transition, the static potential and the mass of the 0^{++} glueball. We found that indeed the lattice artefacts in e.g. m_{0^{++}}/T_c can be reduced considerably compared with the pure Wilson (fundamental) gauge action at the same lattice spacing.