Who turned out the lights?

[Tachyon]

So, if protons decay, is there some way to trap and capture their radiation / mass after the decay?

Proton decay is a consequence of the first Grand Unified Theory, SU(5).

Experiment has ruled out the predicted proton lifetime; thus SU(5) proton decay.

Monopoles induce the same baryon decay; thus Conversion drive technology should be able to capture most of the results (e.g. everything but the neutrinos).