The universality class of the electroweak theory Original Research Article

We study the universality class and critical properties of the electroweak theory at finite temperature. Such critical behaviour is found near the endpoint mH = mH,c of the line of first-order electroweak phase transitions in a wide class of theories, including the Standard Model (SM) and a part of the parameter space of the Minimal Sypersymmetric Standard Model (MSSM). We find that the location of the endpoint corresponds to the Higgs mass mH,c = 72(2) GeV in the SM with sin2 θw = 0, and mH,c < 80 GeV with sin2θw = 0.23. As experimentally mH > 88 GeV, there is no electroweak phase transition in the SM. We compute the corresponding critical indices and provide strong evidence that the phase transitions near the endpoint fall into the three-dimensional Ising universality class.