DOMAIN-WALL FERMIONS WITH MAJORANA COUPLINGS

We examine the lattice boundary formulation of chiral fermions with ei ther an explicit Majorana mass or a Higgs-Majorana coupling introduced on one of the boundaries, We demonstrate that the low-lying spectrum of the models with an explicit Majorana mass of the order of an invers e lattice spacing is chiral at tree level, Within a mean-field approxi mation we show that the systems with a strong Higgs-Majorana coupling have a symmetric phase, in which a Majorana mass of the order of an in verse lattice spacing is generated without spontaneous breaking of the gauge symmetry. We argue, however, that the models within such a phas e have a chiral spectrum only in terms of the fermions that are single ts under the gauge group. The application of such systems to non-pertu rbative formulations of supersymmetric and chiral gauge theories is br iefly discussed. (C) 1997 Published by Elsevier Science B.V.