THE PHASE-DIAGRAM OF A U(1) HIGGS-YUKAWA MODEL AT FINITE LAMBDA

In this paper we investigate how the phase diagram of a U(1) symmetry Higgs-Yukawa system depends on the scalar self-coupling lambda. The ph ase diagram of similar models with continuous symmetry were extensivel y studied in the infinite scalar self-coupling lambda = infinity limit . Recent analytical and numerical calculations at zero self-coupling s howed qualitatively different phase diagram, raising the question of t he lambda-dependence of the phase diagram. Here we use analytical (lar ge-N(f), perturbative and mean-field) approximations as well as numeri cal simulations to investigate the system.