What is the half-life of a proton?
So far, we don’t have any solid evidence that protons do decay. So, we would have to say that its half-life may be infinite. Some Grand Unification Theories (theories attempting to combine the the electromagnetic, weak nuclear, and strong nuclear forces into a single force) predict that protons will eventually decay. However, all attempts to confirm this prediction have failed to detect such a decay. So, physicist theorize that, if protons do decay at all, then their half-lives have to be at least 10^31 years.
