Is a Single Proton Truly Stable or Do Theories Predict Its Decay?

[daumphys]

We know hydrogen atom is stable. Then, single proton is stable? Can we store it for a long time without decay?
Do we have any related equation about particle stability?

 

[Drakkith]

It is currently unknown whether a proton is stable or not. We have never observed one to decay, but it could be either case.

 

[tom.stoer]

In the standard model the proton is stable, but there are various GUT proposals which predict proton decay. Simple models like SU(5) and SO(10) have been ruled out experimentally b/c of the measured minimum proton lifetime; other's are still allowed.