Abstract
Using partial-wave unitarity and the observed density of the Universe, we show that a stable elementary particle which was once in thermal equilibrium cannot have a mass greater than 340 TeV. An extended object which was once in thermal equilibrium cannot have a radius less than 7.5× fm. A lower limit to the relic abundance of such particles is also found.
- Received 5 October 1989
DOI:https://doi.org/10.1103/PhysRevLett.64.615
©1990 American Physical Society