Dynamical fermion mass generation at a tricritical point in strongly coupled U(1) lattice gauge theory

Fermion mass generation in the strongly coupled U(1) lattice gauge theory with fermion and scalar fields of equal charge is investigated by means of numerical simulation with dynamical fermions. The chiral symmetry of this model is broken by the gauge interaction and restored by the Light scalar. We present evidence for the existence of a particular, tricritical point of the corresponding phase boundary where the continuum limit might possibly be constructed. It is of interest as a model for dynamical symmetry breaking and mass generation due to a strong gauge interaction. In addition to the massive and unconfined fermion F and Goldstone boson pi, a gauge ball of mass m(S) similar or equal to 1/2m(F), and some other states are found. The tricritical exponents appear to be nonclassical. [S0556-2821(98)01315-0].