GUT viable w/o SUSY? Could GUT be physically wrong?

  • Context: Graduate 
  • Thread starter Thread starter ensabah6
  • Start date Start date
  • Tags Tags
    Gut Susy
Click For Summary
SUMMARY

The discussion centers on the viability of Grand Unified Theories (GUT) without Supersymmetry (SUSY). It is established that without SUSY, the running gauge couplings of the Standard Model (SM) do not unify, which raises questions about the physical correctness of GUT. The argument posits that while GUTs are not outright ruled out, they face challenges due to rapid proton decay predictions. The Minimal Supersymmetric Standard Model (MSSM) is highlighted for its near-perfect coupling unification, although this may be overstated given the assumptions of minimal new physics.

PREREQUISITES
  • Understanding of Grand Unified Theories (GUT)
  • Familiarity with Supersymmetry (SUSY)
  • Knowledge of Standard Model (SM) gauge couplings
  • Basic concepts of perturbation theory in quantum field theory
NEXT STEPS
  • Research the implications of proton decay in GUT frameworks
  • Study the Minimal Supersymmetric Standard Model (MSSM) and its predictions
  • Explore the role of higher-order corrections in gauge coupling unification
  • Investigate alternative theories to GUT that do not rely on SUSY
USEFUL FOR

The discussion is beneficial for theoretical physicists, cosmologists, and students of particle physics interested in the implications of SUSY on gauge coupling unification and the validity of Grand Unified Theories.

ensabah6
Messages
691
Reaction score
0
One argument in favor of SUSY is that without SUSY, the running gauge coupling unification do not meet for the three forces, but with SUSY they meet around 10^15 GEV. This implies that gauge coupling most meet for GUT to be viable. So without SUSY, the running gauge couplings do not meet.

If SUSY does not exist, then the SM gauging couplings do not meet. Does this imply that GUT are physically wrong?
 
Physics news on Phys.org
ensabah6 said:
If SUSY does not exist, then the SM gauging couplings do not meet. Does this imply that GUT are physically wrong?
Afaik w/o SUSY the gauge couplings are calculated in some order in perturbation theory and are extrapolated over a huge energy range. So for me there is no reason why higher order corrections should not tune the running of couplings.

And as far as I understood GUT is not rules out b/c the couplings do not meet but because all GUTs cause the proton decay too fast.
 
A lot of this game is very sensitive to new physics and calculational sophistication between the electroweak scale and the GUT scale. Absent knowing that, its very hard to say much of anything exactly.

Keep in mind the couplings almost meet with just the standard model physics, so close that even if SuSY didn't exist, it wouldn't be a bad guess to assume that some sort of unification phenomenology takes over.

So of course, you have the famous selling point for the MSSM where the couplings unite almost perfectly. However I would say its oversold putting it that way, as its a little bit fishy b/c it really assumes very little new physics until the unification scale and could be purely coincidental that it seems perfect to us at this time given our limited knowledge of btSM physics. Instead I would say that SuSY has the attractive benefit that it tends to ameliorate coupling constant unification in a range of generic model(s) building. Thats still nontrivial, b/c a priori you might have expected the fit to simply get worse. That it doesn't is a good sign.
 

Similar threads

Graduate Could GUT be wrong (i.e unrealized in nature)?
  • · Replies 16 ·
Replies
16
Views
4K
Graduate What are the implications of a new 750GEV particle to GUTs?
  • · Replies 34 ·
2
Replies
34
Views
5K
Undergrad LHC run 2, does Supersymmetry worsen hierarchy fine tuning
  • · Replies 2 ·
Replies
2
Views
3K
Graduate Implications of a new 17 Mev vector boson on Higgs, SUSY
  • · Replies 74 ·
3
Replies
74
Views
11K
Undergrad Is there a fine structure constant running anomaly?
  • · Replies 2 ·
Replies
2
Views
4K
Graduate Does Peter Woit's solution of Higgs' naturalness problem work?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad What are the Priority Tasks for High Energy Physics Beyond the Standard Model?
  • · Replies 1 ·
Replies
1
Views
3K
Graduate Branching ratios | Higgs phenomenology
  • · Replies 13 ·
Replies
13
Views
4K
Graduate If Dark Matter does not exist, would string/SUSY/GUT be falsified?
  • · Replies 4 ·
Replies
4
Views
4K
Graduate GUTs & Planck Scale: Unifying Gravity?
  • · Replies 5 ·
Replies
5
Views
3K