Improvement via hypercubic smearing in triplet and sextet QCD

We study non-perturbative improvement in SU(3) lattice gauge theory coupled to fermions in the fundamental and two-index symmetric representations. Our lattice action is defined with hypercubic smeared links incorporated into the Wilson-clover fermion kernel. Using standard Schroedinger-functional techniques we estimate the clover coefficient Csw and find that discretization errors are much smaller than in thin-link theories.