Do Protons Decay?

Question

Well, do they?

Well, I asked this question because I wanted to know more about the decay of the universe, and how the "Photon Era" would arise...

http://en.wikipedia.org/wiki/Heat_death_of_the_universe#The_Photon_Age_-_from_10150_years_until_Distant_Time

Answer 1

The half life of the proton is in come circles thought to be a fundamental constant of the universe like the charge of an electron and the speed of light.

However, any model that allows or insists upon proton decay has such a long half life that the odds of actually observing one are too small to bother looking. We're talking 10^31 or so years.

That's 10,000 billion billion billion years.

Its about 7*10^19 times the age of the universe as we think of it today. Even if a proton does decay, its going to be a ridiculous amount of time before there is the slightest statistical chance of observing the event occurring naturally.... Long after humanity is dead and gone.

Do they decay? Nobody knows, but the most promising theories in physics today - the ones with the most mathematical and experimental data to back them up imply that they do indeed decay.

Answer 2

Nobody has ever seen a proton decay. There are theories of particle physics that predict that protons will decay and the half life is on the order of 10^31 years. That is 10^21 times the current age of the universe. The fact that we haven't seen any proton decays has actually disproved some particle theories that predicted half lives of 'only' 10^29 years.

The upshot is that we simply don't know.

Answer 3

According to the Standard Model, no. According to some Grand Unified Theories, yes. It hasn't been observed yet though, and each failed attempt increases the predicted minimum half life - I think it's now up to 10^36 years! That doesn't mean it can't be observed though - it's just highly unlikely for any given proton.

Answer 4

No. Generally speaking a proton will stay a proton forever. There are situations where they can be altered into another type of subatomic particle (such as in the proton-proton chain in hydrogen-fusing stars like our sun) but generally speaking, they don't decay.

Answer 5

Nobody is entirely sure. Some theoretical models do predict a decay, but the half-life is on the order of quadrillions of years, so is completely unobservable.

Answer 6

If left alone, protons are stable and do not decay.

Answer 7

Not if you apply a fresh coat of paint every few years.

Answer 8

If they do it takes longer than the 13.7 billion years they have existed.