Grand Unification - 5.4x10 ^-44 to 10 ^-36  Seconds

Gravity having gone its separate way, the Strong Nuclear Force, The Weak Nuclear Force, and Electromagnetism, remain unified in a single electronuclear force.  The temperature is falling from its value of around 10³²ºK at the start of this period.  Assuming the process of grand unification is correct, at the end of this period the strong nuclear force separates from the other forces after 10^-36 of a second. The temperature falls below 10²⁷ºK, the Grand Unification temperature, so no more X and Y bosons are created.  If the theory is correct, and X and Y bosons did exist, they couple quarks to leptons. 

The problem is that this would permit violation of the conservation of baryon number (B) and the conservation of lepton number (L), but would conserve (B minus L), implying that protons would be unstable and would decay over a long enough period.  A proton, with B = 1& L = 0, decays into a pion, with B = 0 & L = 0, and a positron, with B = 0 & L = -1.  Thus B minus L starts with a value of (1 - 0) = 1, and ends with a value of ((0 + 0) - (0 - 1)) = 1.  Despite numerous experiments, no evidence of proton decay has been found. 

The X and Y bosons decay into various combinations of up/down quarks/anti-quarks, electrons, electron antineutrinos and positrons.  The violation of the conservation of baryon number may result in a small excess of matter over antimatter, providing one possible explanation for Baryogenisis (see section "A Particle Soup").  Once all this is over, it signals the start of the Electroweak epoch where the weak nuclear force and electromagnetism remain joined as the electroweak force. 

Astronomy & Cosmology -

The Early Universe

(or "What Banged in the Big Bang?")