Abstract
We show that there are discrete gauge symmetries which naturally protect heavy particles from decaying into ordinary light particles in the supersymmetric standard model. This makes the proposal that superheavy particles constitute part of the dark matter in the present universe very attractive. It is more interesting that there is a class of discrete gauge symmetries which naturally accommodates a long-lived unstable particle. We find that in some discrete models, for example, a superheavy particle has a lifetime of for a mass of This long lifetime is guaranteed by the absence of lower dimensional operators (of light particles) coupled to the We briefly discuss a possible explanation for the recently observed ultrahigh-energy cosmic ray events by the decay of this unstable particle.
- Received 19 May 1998
DOI:https://doi.org/10.1103/PhysRevD.58.103503
©1998 American Physical Society