Electroweak phase transition: recent results

TL;DR

Recent 4d lattice simulations show that the electroweak phase transition is first order below a certain Higgs mass, but becomes a crossover at higher masses, aligning with dimensional reduction results and excluding the transition in the Standard Model.

Contribution

The paper provides updated lattice simulation results on the electroweak phase transition, confirming the nature of the transition and its dependence on Higgs mass, and compares lattice and perturbative approaches.

Findings

First order transition below 66.5 GeV Higgs mass

Crossover transition above this Higgs mass

Excludes electroweak phase transition in the Standard Model

Abstract

Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.