More on lattice chiral gauge theories with Wilson-Yukawa terms

Abstract

We consider two problems of lattice chiral gauge theories with Wilson-Yukawa terms. First we calculate a fermion-gauge coupling by a hopping parameter expansion. At the leading order we find that the fermion-gauge coupling has a chiral and tree-like structure. We argue that this fermion-gauge coupling remains non-zero in the continuum limit taken in the Higgs phase. Secondly we study how fermion number conservation fails in general regularization schemes. In perturbative regularization schemes we show that the fermion number has to be carried by gauge field configurations with non-zero winding number and this fermion number is not conserved in the presence of instantons. We point out, however, that the fermion number is conserved in lattice chiral gauge theories with Wilson-Yukawa terms.