Related papers: Tunguska Dark Matter Ball
In 1984 Edward Witten proposed that an extremely dense form of matter composed of up, down, and strange quarks may be stable at zero pressure (Witten, 1984). Massive nuggets of such dense matter, if they exist, may pass through the Earth…
Introduction to the meaning of dark matter and a few historical gestures. What it is? By what the dark matter is formed? Experimental phenomenon evidences and relative explanation under the point of view of the physics of the elementary…
An appealing theory is that our current patch of universe was born as a nucleation bubble from a phase of false vacuum eternal inflation. We search for evidence for this theory by looking for the signal imprinted on the CMB that is…
We propose that the totality of dark matter in the universe might ascribe its origin to one of the key properties of cosmological inflation, that it may be eternal: regions that at the end of the primordial accelerated expansion of the…
The idea that dark matter could be made of stable relics of microscopic black holes is not new. In this article, we revisit this hypothesis, focusing on the creation of black holes by the scattering of trans-Planckian particles in the early…
A recent understanding on how quantum effects may affect black-hole evolution opens new scenarios for dark matter, in connection with the presence of black holes in the very early universe. Quantum fluctuations of the geometry allow for…
A one-component dark energy fluid model of the late universe is considered ($w<-1$) when the fluid, initially assumed laminar, makes a transition into a turbulent state of motion. Spatial isotropy is assumed so that only the bulk…
The processes are investigated by which gas loses its angular momentum during the protogalactic collapse phase, leading to disk galaxies that are too compact with respect to the observations. High-resolution N-body/SPH simulations in a…
The evidence is that the mass of the universe is dominated by an exotic nonbaryonic form of matter largely draped around the galaxies. It approximates an initially low pressure gas of particles that interact only with gravity, but we know…
If the mass of dark matter is generated from a cosmological phase transition involving the nucleation of bubbles, the corresponding bubble walls can filter out dark matter particles during the phase transition. Only particles with…
We present a scenario for non-thermal production of dark matter from evaporation of primordial black holes. A period of very early matter domination leads to formation of black holes with a maximum mass of $\simeq 2 \times 10^8$ g, whose…
(To appear in the Astrophysical Journal) Holdom and Malaney (1994) have suggested a mechanism for gamma-ray bursts which requires that stars be captured by a neutrino ball. Neutrino balls would be, for the most part, denser than main…
We consider the early universe at temperatures close to the fundamental scale of gravity (M_D << M_Planck) in models with extra dimensions. At such temperatures a small fraction of particles will experience transplanckian collisions that…
We investigate primordial black hole formation in the matter-dominated phase of the Universe, where nonspherical effects in gravitational collapse play a crucial role. This is in contrast to the black hole formation in a radiation-dominated…
In a class of theories where the Higgs field emerges as a pseudo Nambu-Goldstone boson, it is often assumed that interactions to generate the top Yukawa coupling provide the Higgs potential as well. Such a scenario generically requires a…
If an early matter phase of the Universe existed after inflation with the proper power spectrum, enhanced density perturbations can decouple from the Hubble flow, turn around and collapse. In contrast to what happens in a radiation…
The origin of cosmic gamma-ray bursts remains one of the most intriguing puzzles in astronomy. We suggest that purely general relativistic effects in the collapse of massive stars could account for these bursts. The late formation of closed…
We consider a mechanism of dark matter production in the course of first order phase transition. We assume that there is an asymmetry between X- and anti-X-particles of dark sector. In particular, it may be related to the baryon asymmetry.…
The SLIM experiment at the Chacaltaya high altitude laboratory was sensitive to nuclearites and Q-balls, which could be present in the cosmic radiation as possible Dark Matter components. It was sensitive also to strangelets, i.e. small…
If extra spacetime dimensions and low-scale gravity exist, black holes will be produced in observable collisions of elementary particles. For the next several years, ultra-high energy cosmic rays provide the most promising window on this…