Properties of phase transitions in U(1) and SU(2) lattice Higgs models

The U(1) and SU(2) lattice Higgs models with scalar fields in the fundamental representations have been studied in high statistics Monte Carlo simulation. The authors have completed the phase diagrams of both models by finding several new phase transitions at negative β, and determined the positions of the Higgs phase transitions with great accuracy. The weakening of the first-order Higgs phase transition with increasing λ or β has been demonstrated. At the points λ = 0.5, β = 2.25 and λ = 3, β = 2.5 in the U(1) and SU(2) models, respectively, the authors have found signs of critical behaviour