Electroweak epoch

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 electroweak interaction, but was 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). Some cosmologists place the electroweak epoch at the start of the inflationary epoch, approximately 10−36 seconds after the Big Bang.[2][3][4] 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.[5] Particle interactions in this phase were energetic enough to create large numbers of exotic particles, including stable 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 at observable rates.[citation needed] The remaining W and Z bosons decayed quickly, and the weak interaction became a short-range force in the following quark epoch.

The physics of the electroweak epoch is less speculative and much better understood than the physics of previous periods of the early universe. The existence of W, Z, and Higgs bosons has been demonstrated, and other[which?] predictions of electroweak theory have been experimentally verified. In the minimal Standard Model, the transition during the electroweak epoch was not a first or a second order phase transition but a continuous crossover, preventing any baryogenesis, [6] or the production of an observable gravitational wave background. [7][8] However many extensions to the Standard Model including supersymmetry and the inert doublet model have a first order electroweak phase transition (but still lack additional CP violation).

See alsoEdit


  1. ^ D'Onofrio, Michela and Rummukainen, Kari (2016). "Standard model cross-over on the lattice". Phys. Rev. D93 (2): 025003. arXiv:1508.07161. Bibcode:2016PhRvD..93b5003D. doi:10.1103/PhysRevD.93.025003. hdl:10138/159845.CS1 maint: multiple names: authors list (link)
  2. ^ Ryden, B. (2003). Introduction to Cosmology. Addison-Wesley. p. 196. ISBN 0-8053-8912-1.
  3. ^ Allday, Jonathan (2002). Quarks, Leptons and the Big Bang. Taylor & Francis. p. 334. ISBN 978-0-7503-0806-9.
  4. ^ Our Universe Part 6: Electroweak Epoch, Scientific Explorer
  5. ^ Lecture 13: History of the Very Early Universe Archived 2012-03-27 at the Wayback Machine, Dr. Balša Terzić, Northern Illinois Center for Accelerator and Detector Development
  6. ^ Bergerhoff, Bastian; Wetterich, Christof (1998). "Electroweak Phase Transition in the Early Universe?". Current Topics in Astrofundamental Physics: Primordial Cosmology. Springer Netherlands. pp. 211–240. arXiv:hep-ph/9611462. doi:10.1007/978-94-011-5046-0_6. ISBN 978-94-010-6119-3.
  7. ^ Caprini, Chiara; et al. (2020). "Detecting gravitational waves from cosmological phase transitions with LISA: an update". JCAP. 03: 024. arXiv:1910.13125. doi:10.1088/1475-7516/2020/03/024.
  8. ^ Ghiglieri, J. and Jackson, G. and Laine, M. and Zhu, Y. (2020). "Gravitational wave background from Standard Model physics: Complete leading order". arXiv:2004.11392. Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link)