Related papers: Properties of Gravitationally Bound Dark Compact U…
If dark matter in the form of compact objects comprises a large fraction of the mass of the universe, then gravitational lensing effects on gamma-ray bursts are expected. We utilize BATSE and Ulysses data to search for lenses of different…
We study a minimally extended version of the Standard Model where baryon number is gauged with a $U(1)_B$ symmetry. This model can be made anomaly-free by adding a set of additional fermions. The lightest component of these fermions behaves…
Exotic compact objects with physical surfaces a Planckian distance away from where the horizon would have been are inspired in quantum gravity. Most of these objects are defined by a classical spacetime metric, such as boson stars,…
Various theories of dark matter predict distinctive astrophysical signatures in gravitational-wave sources that could be observed by ground- and space-based laser interferometers. Different candidates-including axions, dark photons,…
Beyond black holes and neutron stars, new hypothetical compact objects have been proposed as potential astrophysical entities. In general, their properties have not yet been fully explored or understood, nor has it been proven whether or…
Dark matter could take the form of dark massive compact halo objects (dMACHOs); i.e., composite objects that are made up of dark-sector elementary particles, that could have a macroscopic mass from the Planck scale to above the solar mass…
We find that the quantum of gravity, the graviton, has time-varying mass (the gomidium), and radius (the somium); both vary with the inverse of R; and its frequency is given by Hubble's parameter. Dark matter can be made of such gravitons.…
Theoretical models of self-interacting dark matter offer a promising solution to several unresolved issues within the collisionless cold dark matter framework. For asymmetric dark matter, these self-interactions may encourage gravitational…
Gravitinos with a mass in the keV range are an interesting candidate for warm dark matter. Recent measurements of the matter density of the universe and of cosmic structures at the dwarf galaxy scale rule out the simplest gravitino models…
In this work we complete a model independent analysis of dark matter constraining its mass and interaction strengths with data from astro- and particle physics experiments. We use the effective field theory framework to describe…
We propose that dark matter consists of collections of atoms encapsulated inside pieces of an alternative vacuum, in which the Higgs field vacuum expectation value is appreciably smaller than in the usual vacuum. The alternative vacuum is…
This article reviews recent progress in observational determination of the properties of dark matter on small astrophysical scales, and progress towards the European Extremely Large Telescope. Current results suggest some surprises: the…
It seems necessary to suppress, at least partially, the formation of structure on subgalactic scales. As an alternative to warm or collisional dark matter, I postulate a condensate of massive bosons interacting via a repulsive interparticle…
The nature of dark matter (DM) remains a profound mystery. Macroscopic candidates, such as Fermi-balls, offer a distinct alternative to conventional particle DM, yet their low number density makes terrestrial detection challenging. In this…
The nature of dark matter is one of the most pressing questions in particle physics. Yet all our present knowledge of the dark sector to date comes from its gravitational interactions with astrophysical systems. Moreover, astronomical…
About one-fourth of the universe is thought to consist of dark matter. Yet there is no clear understanding about the nature of these particles. Commonly discussed dark matter candidates includes the so called WIMPs or weakly interacting…
We review sources of high-frequency gravitational waves, summarizing our current understanding of emission mechanisms, expected amplitudes and event rates. The most promising sources are gravitational collapse (formation of black holes or…
Massive gravity with second and fourth derivatives is shown to give both attractive and repulsive gravities. In contrast to the attractive gravity correlated with the energy-momentum tensor, the repulsive gravity is related to a fixed mass…
Light gravitinos, with mass in the eV to MeV range, are well-motivated in particle physics, but their status as dark-matter candidates is muddled by early-Universe uncertainties. We investigate how upcoming data from colliders may clarify…
Dark matter may consist of weakly interacting elementary particles or of macroscopic compact objects. We show that the statistics of the gravitational lensing of high redshift supernovae strongly discriminate between these two classes of…