Do you believe in proton decay?

For the discussion of the sciences. Physics problems, chemistry equations, biology weirdness, it all goes here.

Moderators: gmalivuk, Moderators General, Prelates

Do you believe in proton decay?

Yes
10
53%
No
9
47%
 
Total votes: 19

scratch123
Posts: 236
Joined: Mon Mar 07, 2011 9:18 pm UTC

Do you believe in proton decay?

Postby scratch123 » Sat May 25, 2013 3:30 pm UTC

http://en.wikipedia.org/wiki/Proton_decay

I have read some good arguments both for and against it so I am not sure what I believe. On one hand some grand unified theories predict it but on the other hand it has never been observed.

snow5379
Posts: 247
Joined: Tue Apr 12, 2011 6:06 pm UTC

Re: Do you believe in proton decay?

Postby snow5379 » Sat May 25, 2013 4:36 pm UTC

I don't feel there is enough evidence to say for sure. Also they might decay under exotic conditions.

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Do you believe in proton decay?

Postby Tass » Sat May 25, 2013 4:47 pm UTC

snow5379 wrote:I don't feel there is enough evidence to say for sure. Also they might decay under exotic conditions.


The definitely decay under certain conditions, like in a beta+ decay. The question is whether the decay in the limit of cold vacuum.

User avatar
Voekoevaka
Posts: 42
Joined: Wed Apr 10, 2013 10:29 am UTC
Location: Over nine thousand.

Re: Do you believe in proton decay?

Postby Voekoevaka » Sat May 25, 2013 5:37 pm UTC

I don't know if I have to believe in or not. That's problematic. I want to know the answer, because I want to know if the universe will end as sparse black holes and positonium, or with iron dust.
I'm a dozenalist and a believer in Tau !

User avatar
poxic
Eloquently Prismatic
Posts: 4751
Joined: Sat Jun 07, 2008 3:28 am UTC
Location: Left coast of Canada

Re: Do you believe in proton decay?

Postby poxic » Sat May 25, 2013 5:52 pm UTC

The poll needs a "mu" option. I'm with Voeketc. in that belief doesn't seem relevant. If someone comes up with convincing proof one way or the other, I'll probably believe that. Until then, it's just a big idunno.
A man who is 'ill-adjusted' to the world is always on the verge of finding himself. One who is adjusted to the world never finds himself, but gets to be a cabinet minister.
- Hermann Hesse, novelist, poet, Nobel laureate (2 Jul 1877-1962)

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Do you believe in proton decay?

Postby Tass » Sat May 25, 2013 6:38 pm UTC

poxic wrote:The poll needs a "mu" option. I'm with Voeketc. in that belief doesn't seem relevant. If someone comes up with convincing proof one way or the other, I'll probably believe that. Until then, it's just a big idunno.


It is a dunno, sure. What he asks is whether you put the probability as higher or lower than fifty percent.

It is very much subject to change with new information, but you must still have a bayesian prior.

User avatar
gmalivuk
GNU Terry Pratchett
Posts: 26765
Joined: Wed Feb 28, 2007 6:02 pm UTC
Location: Here and There
Contact:

Re: Do you believe in proton decay?

Postby gmalivuk » Sat May 25, 2013 7:06 pm UTC

Which could be exactly 50/50, or close enough to it that you're unwilling to believe either option at this point.
Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.
---
If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

(he/him/his)

User avatar
thoughtfully
Posts: 2253
Joined: Thu Nov 01, 2007 12:25 am UTC
Location: Minneapolis, MN
Contact:

Re: Do you believe in proton decay?

Postby thoughtfully » Sun May 26, 2013 12:27 pm UTC

I'd be surprised if they didn't decay, as baryon nonconservation is arguably necessary for us existing at all. B-L is the conserved quantity.

Also monopoles eat protons :) They are made very scarce by inflation, but not eliminated :)
Image
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
-- Antoine de Saint-Exupery

scratch123
Posts: 236
Joined: Mon Mar 07, 2011 9:18 pm UTC

Re: Do you believe in proton decay?

Postby scratch123 » Sun May 26, 2013 5:43 pm UTC

thoughtfully wrote:I'd be surprised if they didn't decay, as baryon nonconservation is arguably necessary for us existing at all. B-L is the conserved quantity.

Also monopoles eat protons :) They are made very scarce by inflation, but not eliminated :)


So how many years do you think proton decay takes? When do you think we will see it in an experiment?

User avatar
thoughtfully
Posts: 2253
Joined: Thu Nov 01, 2007 12:25 am UTC
Location: Minneapolis, MN
Contact:

Re: Do you believe in proton decay?

Postby thoughtfully » Sun May 26, 2013 5:57 pm UTC

scratch123 wrote:
thoughtfully wrote:I'd be surprised if they didn't decay, as baryon nonconservation is arguably necessary for us existing at all. B-L is the conserved quantity.

Also monopoles eat protons :) They are made very scarce by inflation, but not eliminated :)


So how many years do you think proton decay takes? When do you think we will see it in an experiment?

I leave the fiddly details to the experimentalists.
Image
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
-- Antoine de Saint-Exupery

User avatar
doogly
Dr. The Juggernaut of Touching Himself
Posts: 5531
Joined: Mon Oct 23, 2006 2:31 am UTC
Location: Lexington, MA
Contact:

Re: Do you believe in proton decay?

Postby doogly » Tue May 28, 2013 6:53 pm UTC

thoughtfully wrote:Also monopoles eat protons :) They are made very scarce by inflation, but not eliminated :)

Well, if you think monopoles exist. They are also absent in SM.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?

User avatar
gmalivuk
GNU Terry Pratchett
Posts: 26765
Joined: Wed Feb 28, 2007 6:02 pm UTC
Location: Here and There
Contact:

Re: Do you believe in proton decay?

Postby gmalivuk » Tue May 28, 2013 7:40 pm UTC

gmalivuk wrote:Which could be exactly 50/50, or close enough to it that you're unwilling to believe either option at this point.
In fact, I don't think I'd report belief in any proposition to which I ascribe less than a solid 80% or greater probability.
Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.
---
If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

(he/him/his)

User avatar
yurell
Posts: 2924
Joined: Sat Nov 13, 2010 2:19 am UTC
Location: Australia!

Re: Do you believe in proton decay?

Postby yurell » Wed May 29, 2013 8:44 am UTC

What happened to good old 5σ? =P
But at any rate, I believe protons may decay, but I do not hold a positive belief that they day, nor that they do not. OP will have to define 'believe' better — does it mean we accept the mathematical framework of models that suggest protons decay as thus-far consistent with reality but haven't found any positive evidence to support it? If so, I believe 'believe' is the wrong word to use.
cemper93 wrote:Dude, I just presented an elaborate multiple fraction in Comic Sans. Who are you to question me?


Pronouns: Feminine pronouns please!

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Do you believe in proton decay?

Postby Tass » Wed May 29, 2013 11:57 am UTC

gmalivuk wrote:
gmalivuk wrote:Which could be exactly 50/50, or close enough to it that you're unwilling to believe either option at this point.
In fact, I don't think I'd report belief in any proposition to which I ascribe less than a solid 80% or greater probability.


Okay. Fair enough, I guess. The question does not give a rigorous definition of the meaning of "believe"

If forced to answer when no "I don't know" option is given, I would simply cut at fifty percent.

At 80% if I was asked without options for the answer, then I would still answer: "yes", but qualify it with: "but I am not sure".

I is my understanding, though, that people will generally state a very confident belief even when they are less than 80% sure, since people in general vastly overestimate their certainty.

stianhat
Posts: 175
Joined: Mon Jun 13, 2011 6:31 pm UTC

Re: Do you believe in proton decay?

Postby stianhat » Wed May 29, 2013 12:50 pm UTC

The question is perhaps better phrased like this:

What would *surprise you more*, if shown the proof of a) existence of proton decy or b) nonexistence of proton decay?

User avatar
yurell
Posts: 2924
Joined: Sat Nov 13, 2010 2:19 am UTC
Location: Australia!

Re: Do you believe in proton decay?

Postby yurell » Wed May 29, 2013 1:49 pm UTC

(b), because proving a negative like that would be virtually impossible.
cemper93 wrote:Dude, I just presented an elaborate multiple fraction in Comic Sans. Who are you to question me?


Pronouns: Feminine pronouns please!

User avatar
doogly
Dr. The Juggernaut of Touching Himself
Posts: 5531
Joined: Mon Oct 23, 2006 2:31 am UTC
Location: Lexington, MA
Contact:

Re: Do you believe in proton decay?

Postby doogly » Wed May 29, 2013 2:19 pm UTC

It would be completely baffling if someone could prove the nonexistence. All we have right now is the fact that it has never been observed and the standard model doesn't predict it. If someone could somehow prove that no possible future physicses could include it, that would be astonishing.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?

User avatar
eSOANEM
:D
Posts: 3652
Joined: Sun Apr 12, 2009 9:39 pm UTC
Location: Grantabrycge

Re: Do you believe in proton decay?

Postby eSOANEM » Wed May 29, 2013 4:11 pm UTC

The only way to do b would be if someone could mathematically demonstrate that proton decay was inconsistent with some well-observed phenomenon regardless of the theoretical framework. I'm pretty sure that such a statement would have to be so general as to be meaningless (the requirement to be independent of theoretical framework would make the definition of proton difficult) so I'm pretty sure such a thing is completely impossible.

The best you could do would be to show that proton decay would produce (in some limit where existing theories hold approximately) some violation of a well accepted principle (like conservation of momentum). This is potentially provable but even then doesn't disprove proton decay because we could equally reject conservation of momentum (or whatever the principle inconsistent with proton decay was). We'd end up in a situation like with Bell's theorem (e.g. a here are 3 things, pick 2).
my pronouns are they

Magnanimous wrote:(fuck the macrons)

User avatar
thoughtfully
Posts: 2253
Joined: Thu Nov 01, 2007 12:25 am UTC
Location: Minneapolis, MN
Contact:

Re: Do you believe in proton decay?

Postby thoughtfully » Wed May 29, 2013 5:03 pm UTC

Are there any contenders for a beyond the SM theory that don't permit proton decay? I'll allow that some have bizarroly-long, nigh infinite lifetimes, but in principle they aren't stable? Hey, Wikipedia to the rescue! Looks like there is one. Still, the odds are not good.
Image
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
-- Antoine de Saint-Exupery

User avatar
doogly
Dr. The Juggernaut of Touching Himself
Posts: 5531
Joined: Mon Oct 23, 2006 2:31 am UTC
Location: Lexington, MA
Contact:

Re: Do you believe in proton decay?

Postby doogly » Wed May 29, 2013 5:05 pm UTC

But there's also no obvious need for BSM physics at all.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?

User avatar
eternauta3k
Posts: 519
Joined: Thu May 10, 2007 12:19 am UTC
Location: Buenos Aires, Argentina

Re: Do you believe in proton decay?

Postby eternauta3k » Wed May 29, 2013 5:13 pm UTC

Neutrino oscillations?

Keeping researchers employed?
VectorZero wrote:It takes a real man to impact his own radius

That's right, slash your emo-wrists and spill all your emo-globin

User avatar
doogly
Dr. The Juggernaut of Touching Himself
Posts: 5531
Joined: Mon Oct 23, 2006 2:31 am UTC
Location: Lexington, MA
Contact:

Re: Do you believe in proton decay?

Postby doogly » Wed May 29, 2013 5:27 pm UTC

eternauta3k wrote:Neutrino oscillations?

Keeping researchers employed?


Oh word, neutrinos. Though you can do minimalistic modifications for that rather than GUTs.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?

User avatar
thoughtfully
Posts: 2253
Joined: Thu Nov 01, 2007 12:25 am UTC
Location: Minneapolis, MN
Contact:

Re: Do you believe in proton decay?

Postby thoughtfully » Wed May 29, 2013 6:52 pm UTC

Inflation? The crazy vacuum energy? Unification of forces? Quantum gravity?
The baryon/antibaryon asymmetry? Dark matter/energy?
There's a 120 orders of magnitude error for the cosmological constant.
That's a glaring disagreement with observation almost as severe as existing at all.
Image
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
-- Antoine de Saint-Exupery

User avatar
doogly
Dr. The Juggernaut of Touching Himself
Posts: 5531
Joined: Mon Oct 23, 2006 2:31 am UTC
Location: Lexington, MA
Contact:

Re: Do you believe in proton decay?

Postby doogly » Wed May 29, 2013 8:55 pm UTC

So, you can construe the cosmological constant to be a part of the matter side of the equation, in which case it should be the vacuum energy of... some field. Or, you can construe it on the curvature side, in which case the GR Lagrangian now has two parameters, G_newton and Lambda. It's just part of the specification of the theory. Taken that way I think it makes perfect sense.

"naturalness" and these order of magnitude "expected values" just don't sound compelling to me. In particular this 120 order of magnitude story is what happens when you renormalize with an extremely naive cutoff. Just don't do that. That is dumb.

Inflation might be nice - it's a nifty heuristic but with disappointing models. Do most inflation schemes fit into a GUT though? I didn't think so, it seems mostly like they just go for "toss on a bonus scalar field," but maybe those are "toy" models only that people like to bring up in talks, but in the back of their head they imagine it coming out of a larger GUT.

Quantum Gravity also has nothing to do with the standard model of particle physics. Some quantum gravities, like string theory, do modify the particle content, but many others do not.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.

Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?

User avatar
eternauta3k
Posts: 519
Joined: Thu May 10, 2007 12:19 am UTC
Location: Buenos Aires, Argentina

Re: Do you believe in proton decay?

Postby eternauta3k » Thu May 30, 2013 12:48 am UTC

doogly wrote:Oh word, neutrinos. Though you can do minimalistic modifications for that rather than GUTs.
I don't understand why they don't just stick a mass term in there (after simmetry breaking). We already have huge mass ratios, so what's a couple more orders of magnitude gonna do?
VectorZero wrote:It takes a real man to impact his own radius

That's right, slash your emo-wrists and spill all your emo-globin

SU3SU2U1
Posts: 396
Joined: Sun Nov 25, 2007 4:15 am UTC

Re: Do you believe in proton decay?

Postby SU3SU2U1 » Thu May 30, 2013 1:12 am UTC

Neutrino oscillations?


Keep in mind that this depends very much on what you mean by standard model. I would use it to mean a collection of matter fields and SU3-SU2-U1 symmetry. In this framework, neutrino masses require no modification to the standard model- they are simply the first dimension 5 operator in the standard model. Some people don't like this because they are committed to certain views on renormalization, I like it because I don't think there is any physical principle that leads us to believe things HAVE to be renormalizable- after all neither GR nor the standard model are, and what else is there?

"naturalness" and these order of magnitude "expected values" just don't sound compelling to me.


They probably shouldn't- you can show that "naturalness" is highly regulator dependent. Everyone thought it was a problem because everyone was using Pauli-Villars regulators at the time. Nowadays, using dimensional regulation is so prevalent that students get confused when you pull out Pauli-Villars in the one instance. I think Chris Hill wrote a paper a few years back arguing that we should solve the naturalness problem entirely by making a symmetry argument that dim reg. is the correct approach.

Do most inflation schemes fit into a GUT though?


Many GUTs have such high dimensional higgs fields that you can take many, many (many!) paths to break all the way down to QCD+eletriomagnetism, so its trivially easy to kludge things together to make inflation happen. In the context of GUTs you use this to get rid of the inevitable monopole problem.


Return to “Science”

Who is online

Users browsing this forum: No registered users and 14 guests