Question about time and/or temperature of GUT symmetry breaking

1. Nov 21, 2015

Buzz Bloom

I understand there are quite a few GUT candidates. I also understand that among these candidates some are considered by the theoretical physics community to be more likely to be correct than others.

I am curious about what each of the various GUT candidates predicts as the time (relative to other cosmological events) and/or the temperature at which GUT symmetry breaking occurred. I would also appreciate for each candidate an estimate of the likelihood it will eventually turn out to be accepted as the "correct" GUT.

I would like to calculate for time and temperature composite (logarithmic) mean estimates (with error ranges) weighted by the likelihood estimates.

2. Nov 21, 2015

fzero

The GUT scale would be determined by using the renormalization group to run the electromagnetic, weak, and strong coupling constants up to a high scale and looking for a scale $M_\text{GUT}$ at which all 3 become equal. Once this is done, you can determine an equivalent temperature as $M_\text{GUT}c^2/k_B$. The associated time would be something like $\hbar/(M_\text{GUT}c^2)$.

I'm not aware of any collection of detailed results for the GUT scale for a collection of models. You'd need to dig through the literature or learn how to do the RG running yourself. No one could assign any meaningful likelihood that a GUT would be correct.

3. Nov 21, 2015

Buzz Bloom

Hi fzero:

I am of course disappointed that the information I am looking for doesn't exist, and that I know I don't have the skills to do the research myself. Perhaps you might be able to help me by recommending some references about about the various GUTs that distinguish one from another, and a reference to how to do the RG running myself.. That would be a start at least.

Regards,
Buzz

4. Nov 21, 2015

fzero

As a short overview, I would suggest http://pdg.lbl.gov/2015/reviews/rpp2014-rev-guts.pdf [Broken] from the PDG. For an exhaustive review of non-SUSY GUTs, look at Langacker, Grand Unified Theories and Proton Decay, Phys.Rept. 72 (1981) 185. For SUSY GUTs, Raby has a shorter review at http://arxiv.org/abs/1101.2457. Section 2 of that is an overview of coupling constant unification and the RG equations, but it might not mean that much if you haven't already studied renormalization in QFTs before.

Last edited by a moderator: May 7, 2017
5. Nov 22, 2015

Buzz Bloom

Hi fzero:

I mush appreciate your post, and especially the references. I suspect from your description in the quote that it will be unintelligible to me, since I have never studied renormalization before, but I expect I will find something of interest anyway.

Regards,
Buzz