Abstract
We obtain new stringent constraints on a light spinless particle coupled only to photons at low energies, considering its effects on the extragalactic photon background, the black-body spectrum of the cosmic microwave background radiation and the cosmological abundance of deuterium.
- Received 6 February 1997
DOI:https://doi.org/10.1103/PhysRevD.55.7967
©1997 American Physical Society