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…
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…
Direct Detection of Hawking Radiation from Asteroid-Mass Primordial Black Holes
Profumo, Stefano; Coogan, Adam; Morrison, Logan
Light, asteroid-mass primordial black holes, with lifetimes in the range between hundreds to several millions times the age of the Universe, are well-motivated candidates for the cosmological dark matter. Using archival COMPTEL data, we improve over current constraints on the allowed parameter space of primordial black holes as dark matter by stud…
Neutrino and Positron Constraints on Spinning Primordial Black Hole Dark Matter
Ray, Anupam; Laha, Ranjan; Dasgupta, Basudeb
Primordial black holes can have substantial spin—a fundamental property that has a strong effect on its evaporation rate. We conduct a comprehensive study of the detectability of primordial black holes with non-negligible spin, via the searches for the neutrinos and positrons in the MeV energy range. Diffuse supernova neutrino background searches …
Primordial Black Holes as a Dark Matter Candidate Are Severely Constrained by the Galactic Center 511 keV γ -Ray Line
Laha, Ranjan
We derive the strongest constraint on the fraction of dark matter that can be composed of low mass primordial black holes by using the observation of the Galactic Center 511 keV γ -ray line. Primordial black holes of masses ≲1015 kg will evaporate to produce e± pairs. The positrons will lose energy in the Galactic Center, bec…
Constraining Primordial Black Hole Abundance with the Galactic 511 keV Line
DeRocco, William; Graham, Peter W.
Models in which dark matter consists entirely of primordial black holes (PBHs) with masses around 1 017 g are currently unconstrained. However, if PBHs are a component of the Galactic dark matter density, they will inject a large flux of energetic particles into the Galaxy as they radiate. Positrons produced by these black holes will su…
Search for Gravitational Waves Associated with γ-ray Bursts Detected by the Interplanetary Network
Lee, H. M.; Cline, T.; Hurley, K. +899 more
We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significan…
Is There a Dark Matter Signal in the Galactic Positron Annihilation Radiation?
Rothschild, R. E.; Higdon, J. C.; Lingenfelter, R. E.
Assuming Galactic positrons do not go far before annihilating, a difference between the observed 511 keV annihilation flux distribution and that of positron production, expected from β+ decay in Galactic iron nucleosynthesis, was evoked as evidence of a new source and signal of dark matter. We show, however, that the dark matter sources…
Stringent Constraint on Galactic Positron Production
Beacom, John F.; Yüksel, Hasan
The intense 0.511 MeV gamma-ray line emission from the Galactic Center observed by INTEGRAL requires a large annihilation rate of nonrelativistic positrons. If these positrons are injected at even mildly relativistic energies, higher-energy gamma rays will also be produced. We calculate the gamma-ray spectrum due to inflight annihilation and compa…
Gamma-Ray Constraint on Galactic Positron Production by MeV Dark Matter
Bertone, Gianfranco; Beacom, John F.; Bell, Nicole F.
The Galactic positrons, as observed by their annihilation gamma-ray line at 0.511 MeV, are difficult to account for with astrophysical sources. It has been proposed that they are produced instead by dark matter annihilation or decay in the inner Galactic halo. To avoid other constraints, these processes are required to occur “invisibly,” such that…