Grand unification epoch
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In physical cosmology, assuming that nature is described by a GUT, the grand unification epoch was the period in the evolution of the early universe following the Planck epoch, in which the temperature of the universe was comparable to the characteristic temperatures of grand unified theories. If the grand unification energy is taken to be 1015 GeV, this corresponds to temperatures higher than 1027 K. During this period the four fundamental interactions were indistinguishable from one another, and physical characteristics such as mass, charge, flavour and colour charge were meaningless.
The grand unification epoch ended at approximately 10-35 seconds after the Big Bang. At this point several key events took place. The strong force separated from the other fundamental forces. The temperature fell below the threshold at which X and Y bosons could be created, and the remaining X and Y bosons decayed. It is possible that some part of this decay process violated the conservation of baryon number and gave rise to a small excess of matter over antimatter (see baryogenesis). This phase transition is also thought to have triggered the process of cosmic inflation that dominated the development of the universe during the followng inflationary epoch.
[edit] References
Allday, Jonathan (2001). Quarks, Leptons and the Big Bang. Institute of Physics Publishing. ISBN 978-0750308069.
