Are There GUTs Where the Proton Never Decays?

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SUMMARY

The discussion centers on the existence of Grand Unified Theories (GUTs) where protons do not decay. Participants reference the Super-Kamiokande experiment, which established a lower bound on proton decay lifetime at approximately 1.6 x 1034 years as of 2017. The conversation highlights the challenges in creating models that naturally incorporate proton stability and the implications of marginal differences in decay lifetimes. Additionally, the participants express skepticism about the feasibility of distinguishing between theories of proton decay and absolute stability.

PREREQUISITES
  • Understanding of Grand Unified Theories (GUTs)
  • Familiarity with proton decay processes, specifically p → eμτ
  • Knowledge of baryon number conservation principles
  • Awareness of experimental physics, particularly the Super-Kamiokande experiment
NEXT STEPS
  • Research the implications of proton decay limits set by Super-Kamiokande
  • Explore models of proton stability in the context of GUTs
  • Study baryon number violation and its significance in particle physics
  • Investigate the concept of infinite quantization as proposed by Mark Srednicki
USEFUL FOR

Physicists, researchers in particle physics, and students studying Grand Unified Theories and proton decay phenomena.

billtodd
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Are there any GUTs where the proton never decays?
One should write such a theory, perhaps me... :oldbiggrin:
 
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billtodd said:
Are there any GUTs where the proton never decays?
Where have you looked to find out?

billtodd said:
One should write such a theory, perhaps me... :oldbiggrin:
That is off topic here, since PF is not for personal research.
 
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PeterDonis said:
Where have you looked to find out?
He asked us!
 
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(Thread prefix changed "A"-->"I")
 
It;s fairly trivial to do this. Protons decay via p \rightarrow e \mu \tau and neutrons via n \rightarrow 3\nu. The harder part is to make a model that does this "naturally".
 
Vanadium 50 said:
He asked us!
I looked at Wikipedia (German version) and got a brief, but sufficient answer. The English version is far more detailed so I didn't read it since I already had the main questions answered.

The question I would really like to be answered is: If it is true that Super-Kamiokande in Japan set a lower bound of ##1.6\cdot 10^{34}\,a## (by ##2017##), which are the consequences of this extremely marginal difference to stability. Admittedly, nearly zero and zero make a big difference in mathematics. But if I add the tolerance of measurement in the real world, can it ever be distinguished?
 
Are you worried about losing a sock to its protons decaying? Then you don't care if the lifetime has 34 or 36 zeroes. If you care which theory is right, then you do.
 
Vanadium 50 said:
Are you worried about losing a sock to its protons decaying? Then you don't care if the lifetime has 34 or 36 zeroes. If you care which theory is right, then you do.
Sure. I just wondered if they are distinguishable at all! Or in other words: are there other possible tests with higher expectations of success than starring at a huge tank and waiting forever? And if we detect something, can we be sure it wasn't just noise?
 
  • #10
You can stare at a small tank for an even longer time. Most people don't consider this a step forward.
 
  • #11
fresh_42 said:
which are the consequences of this extremely marginal difference to stability
Um, the difference between not observing anything that would indicate that a proton decay had happened, and observing such a thing? The former is what happened with Super Kamiokande. But if the latter had happened, it would have made a difference.
 
  • #12
Vanadium 50 said:
It;s fairly trivial to do this. Protons decay via p \rightarrow e \mu \tau and neutrons via n \rightarrow 3\nu. The harder part is to make a model that does this "naturally".
I know that neutron can decay (15 minutes in the limelight).
But I think that proton decay is impossible.
@PeterDonis you are right I haven't searched, I thought you knew of the existence of at least one theory that suggests an eternity lifetime for protons,,,,
 
  • #13
pinball1970 said:
In the abstract they write:"However, abandoning the requirement of absolute proton stability"

If there's no absolute stability shouldn't it decay eventually? That's not seems what I was looking for.
But thanks, I guess I really need to read my Group Theory books for physicists.
BTW does anyone know where may I find the report/article of Infinite Quantization by Mark Srednicki, was it ever published?
 
  • #14
billtodd said:
I think that proton decay is impossible.
Based on what?

billtodd said:
I haven't searched
Then you should. The answer to your question is easy to find, and I don't see why you should expect someone else to do that work for you.
 
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  • #15
billtodd said:
But I think that proton decay is impossible.
Thank you for sharing your opinion.

The putative neutron decay n \rightarrow 3\nu gets lumped in with "proton decay" as both processes violate baryon number conservation. The ordinary neutron decay n \rightarrow pe\nu does not.
 
  • #16
PeterDonis said:
Based on what?
Call it my GUT feeling...
 
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  • #17
billtodd said:
Call it my GUT feeling...
Personal speculation is off limits here.

Thread closed.
 

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