Search Publications
Irreducible Axion Background
Rodd, Nicholas L.; Langhoff, Kevin; Outmezguine, Nadav Joseph
Searches for dark matter decaying into photons constrain its lifetime to be many orders of magnitude larger than the age of the Universe. A corollary statement is that the abundance of any particle that can decay into photons over cosmological timescales is constrained to be much smaller than the cold dark-matter density. We show that an irreducib…
No Evidence for Axions from Chandra Observation of the Magnetic White Dwarf RE J0317-853
Safdi, Benjamin R.; Dessert, Christopher; Long, Andrew J.
Axions with couplings ga γ γ∼few ×10-11 GeV-1 to electromagnetism may resolve a number of astrophysical anomalies, such as unexpected ∼TeV transparency, anomalous stellar cooling, and x-ray excesses from nearby neutron stars. We show, however, that such axions are severely constrained by the nonobservation of x ray…
Cosmic Coincidences of Primordial-Black-Hole Dark Matter
Silk, Joseph; Wu, Yi-Peng; Pinetti, Elena
If primordial black holes (PBHs) contribute more than 10% of the dark matter (DM) density, their energy density today is of the same order as that of the baryons. Such a cosmic coincidence might hint at a mutual origin for the formation scenario of PBHs and the baryon asymmetry of the Universe. Baryogenesis can be triggered by a sharp transition o…