A class of chiral fermion models

We study the relation between the Roma and Zaragoza proposals for chiral fermions on the lattice. The fermion action in the Roma approach is shown to be equivalent to one of the Zaragoza type. This result is used to perform a mean-field study of the phase diagram for chiral Yukawa models based on the Roma action. The phase diagram is compared with the one based on the Zaragoza model with the most local choice for the fermion interactions.
Comment: Version to appear in Nucl. Phys. B. Some general discussion added to the Introduction and Conclusion sections. Now 33 pages Latex; style files and (unchanged) PostScript figures again attached in uufiles format