Are There GUTs Where the Proton Never Decays?

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Discussion Overview

The discussion revolves around the existence of Grand Unified Theories (GUTs) in which protons do not decay. Participants explore theoretical implications, experimental observations, and the nature of proton stability within the context of particle physics.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants question whether any GUTs can be formulated that allow for protons to remain stable indefinitely.
  • One participant mentions that protons decay through specific processes, while noting that creating a model that naturally incorporates this decay is more complex.
  • Another participant references the Super-Kamiokande experiment, discussing its findings on proton decay and the implications of the lower bound on proton lifetime.
  • Concerns are raised about distinguishing between different theories of proton decay based on the extremely long lifetimes suggested by experiments.
  • Some participants express skepticism about the possibility of proton decay, suggesting it may be impossible, while others challenge this view and encourage further research.
  • There is mention of a specific article that discusses abandoning the requirement of absolute proton stability, prompting questions about the implications of such a stance.
  • One participant expresses a desire for more accessible tests or observations that could provide clearer insights into proton decay versus stability.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether GUTs can exist where protons never decay. There are competing views on the feasibility of proton decay and the implications of experimental results, indicating an unresolved debate.

Contextual Notes

Participants reference various theoretical frameworks and experimental results, but there are limitations in the discussion regarding the assumptions made about proton stability and the definitions of decay processes. Some mathematical and theoretical aspects remain unresolved.

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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