In
physical cosmology the
electroweak epoch was the period in the evolution of the early universe when the temperature of the universe was high enough to merge
electromagnetism and the
weak interaction into a single
electroweak interaction (> 100
GeV). The electroweak epoch began when the
strong force separated from the electroweak interaction. Some cosmologists place this event at the start of the
inflationary epoch, approximately 10
-36 seconds after the
Big Bang. 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. Particle interactions in this phase were energetic enough to create large numbers of
exotic particles, including
W and Z bosons and
Higgs bosons. As the universe expanded and cooled, interactions became less energetic and when the universe was about 10
-12 seconds old, W and Z bosons ceased to be created. The remaining W and Z bosons decayed quickly, and the weak interaction became a short-range force in the following
quark epoch.