Proton Decay Search
In our Standard Model of particle physics, the proton is assumed to be absolutely stable. However, the Grand Unified Theories (GUTs), which can unify the fundamental forces of nature (electromagnetic, weak nuclear and strong nuclear forces) predict that the proton can decay into lighter energetic charged particles such as electrons muons, pions or others which can be observed. Some of the simplest GUTs have already been completely ruled out by Kamiokande.
Super-Kamiokande is the largest detector for the observation of proton decay in the world. So far, no candidate proton decay events are observed and it is found that the life time of the proton is more than 8.2 x 1033 years for the decay to a positron and a neutral pion.
One of the predicted proton decay mode: