In physical cosmology, the electroweak epoch was the period in the evolution of the early universe when the temperature of the universe had fallen enough that the strong force separated from the electronuclear interaction, but was still high enough for electromagnetism and the weak interaction to remain merged into a single electroweak interaction above the critical temperature for electroweak symmetry breaking (159.5±1.5 GeV[1] in the Standard Model of particle physics).
[2][3] Others place it at approximately 10−32 seconds after the Big Bang, when the potential energy of the inflaton field that had driven the inflation of the universe during the inflationary epoch was released, filling the universe with a dense, hot quark–gluon plasma.
[citation needed] The remaining W and Z bosons decayed quickly, and the weak interaction became a short-range force in the following quark epoch.
Speculation in the 1990s that it may be a first order transition suggested it could source a gravitational wave background[5][6] and a baryogenesis,[7][8] provided the Sakharov conditions are satisfied[9] and the Higg boson energy was below 45 GeV.
[10] Subsequent work with the Standard Model and a measurement of the Higg boson as over 114GeV, showed the transition during the electroweak epoch was not a first- or a second-order phase transition but a continuous crossover, preventing any baryogenesis,[11][12] or the production of an observable gravitational wave background.