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Originally Posted by OngBonga
Thanks for that detailed answer.
Originally Posted by OngBonga
I have another question...
Keep 'em comin'.
Originally Posted by OngBonga
How did light behave in the electoweak world?
Light is light. Photons are photons. They behaved the same then as now. They mediate the electromagnetic interactions. By mediate, I mean they are the exchange particles which express transfers of momentum. Changes in momentum over time are forces, recall. F = dp/dt, where F is force, dp is a small change in momentum, dt is a small change in time, and dp/dt is the incremental change in momentum over an incremental change in time.
What changed is the W and Z bosons. They mediate the weak nuclear interactions. I'm not an expert on symmetry breaking, and that's what all the information on this topic cites. What I understand about symmetry breaking is that as things get colder, the randomness of the particles lessens, and patterns can emerge.
E.g. Iron above the Curie temperature is non-magnetic, because the thermal motions of the particles make all the internal magnets align randomly. As the metal cools, the magnets' forces of interaction with each other are no longer dominated by the thermal forces of collisions, and the magnets begin to align. The rise of a permanent magnetic field as the Iron cools is a spontaneous symmetry breaking.
I can speak to the reference in our discussion of thermal energy in the early universe. The rest mass of the W and Z bosons is 80 GeV/c^2 and 90 GeV/c^2. So when the average thermal energy of the universe was greater than ~100 GeV, these particles could spontaneously manifest themselves in the universe, so the population was insanely much higher than after this period (the electroweak epoch) ended. Of course, they were likely to get blasted apart by anything they interacted with, so they were popping in and out of the universe in a constant wash. Symmetry.
I presume that weak interactions were commonplace during this epoch, that quarks were freely changing their "flavor" constantly, due to interactions with the proliferation of W and Z bosons about. This means that protons and neutrons weren't so stable, and probably that loads of exotic particles were more abundant.
Once the average thermal energy of the universe cooled below ~80 MeV, W and Z bosons could no longer be spontaneously created from the background wash of energy in the universe, so they would have decayed in their normal time and the universe was basically the one we observe today, with 4 forces. Broken symmetry.
Originally Posted by OngBonga
What about before when the strong force (assumingly) unified with EW?
This is entirely hypothetical. Grand Unified Theories happen prior to electroweak epoch, by necessity. It is not clear if any hypotheses accurately describe the universe prior to the electroweak epoch.
Even the electroweak theory has some questionable parts, but mostly is solid theory. The existence of the W and Z bosons, as well as the Higgs, were predicted by electroweak theory prior to their observation. Once again, this is a hallmark of good science, and supplies great credibility to the theory.
One part that is up for debate is when, exactly, the electroweak epoch happened. Some hypotheses place is as early as 10^-36 s after the big bang, while others place it at 10^-12 s after the big bang.
As far as I understand it, the establishment of the credibility of the electroweak theory is why we believe the Standard Model is an accurate description (excellent approximation) of the universe from after the end of inflation up to now, and why we believe the laws of physics have been constant for at least that long.
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