General properties of the decay amplitudes for massless particles · HackerPapers discussions

General properties of the decay amplitudes for massless particles — mentioned by kmm

Fri, 19 Apr 2024 20:14:17 GMT

> You cannot decay if you don’t experience time That's a common misconception, there's no a priori reason a particle without a restframe can't decay. For all known particles with a finite lifetime we give this lifetime as measured in its restframe (i.e. with the particle standing still), but in principle it is an observer-dependent quantity, faster moving particles will take longer to decay. If we, for example, assume the lifetime of a massless particle is proportional to its energy, we retain the same expected Lorentz covariance. Of course, if you actually go through the math, the known…

Paper and discussion history. A mention is not an endorsement.

General properties of the decay amplitudes for massless particles — mentioned by kmm

Tue, 15 Feb 2022 22:09:41 GMT

Only two of the three neutrinos need to be massless, though that would be quite a curious asymmetry, and everyone expects all three to have mass. A massless particle might not have a restframe or experience proper time, but it still propagates through spacetime, and can definitely decay to other massless particles, at least in theory. After all, moving at the speed of light doesn't preclude it from interacting with ordinary matter either. "Luckily", in our universe there are theoretical reasons for photons to be completely stable (e.g. see https://arxiv.org/abs/hep-th/9508018 ), but there's…

Paper and discussion history. A mention is not an endorsement.