Collapsing collisionless particle systems form gravitational bound halos with cuspy density profiles. Also hierarchical merging of these systems produce remnants with cuspy central density profiles. These results lead to the assumption of cuspy NFW [5] profiles for the density distribution in dark matter halos. However, observed rotation curves in disk galaxies suggest dark matter halos with is...

Even when the Higgs particle is finally detected, it will continue to be a legitimate question to ask whether the inertia of matter as a reaction force opposing acceleration is an intrinsic or extrinsic property of matter. General relativity specifies which geodesic path a free particle will follow, but geometrodynamics has no mechanism for generating a reaction force for deviation from geodesi...

Cosmological observations suggest the existence of two different kinds of energy densities dominating at small (< ∼ 500 Mpc) and large (> ∼ 1000 Mpc) scales. The dark matter component, which dominates at small scales, contributes Ωm ≈ 0.35 and has an equation of state p = 0, while the dark energy component, which dominates at large scales, contributes ΩV ≈ 0.65 and has an equation of state p ≃ ...

The gravitational tug of galaxies on orbiting stars, gas clouds, other galaxies, and light reveals that the galaxies have much more mass than their visible constituents provide [1]. From what we know of the primordial abundances of the lightest elements, over 80% of this dark matter is not made of baryons, that is, particles like protons and neutrons, but rather consists of particles not yet ob...

Dark matter clustered in galaxies or clusters is usually interpreted as a new type of material substance subject only to gravitational force. Alternative explanations envisage deviations of the laws of gravity, of the equations of motion or of both from their commonly accepted form. The additional possibility is explored here that the true origin of the effects depicted as “dark matter” should ...

Mirror matter is predicted to exist if parity is an unbroken symmetry of nature. Currently, there is a large amount of evidence that mirror matter actually exists coming from astrophysics and particle physics. One of the most fascinating (but speculative) possibilities is that there is a significant abundance of mirror matter within our solar system. If the mirror matter condensed to form a lar...

A new Solar System population of Weakly Interacting Massive Particle (WIMP) dark matter has been proposed to exist. We investigate the implications of this population on indirect signals in neutrino telescopes (due to WIMP annihilations in the Earth) for the case when the WIMP is the lightest neutralino of the MSSM, the minimal supersymmetric extension of the standard model. The velocity distri...

We consider the possibility of constraining decaying dark matter by looking out through the Milky Way halo. Specifically we use Chandra blank sky observations to constrain the parameter space of sterile neutrinos. We find that a broad band in parameter space is still open, leaving the sterile neutrino as an excellent dark matter candidate. Subject headings: dark matter — elementary particles — ...

One of the main purposes of Statistical Physics is to understand the macroscopic behavior of microscopic systems. For regular matter, composed of negative (electrons) and positive (nuclei) charges, this question is highly non trivial because of the long range of the Coulomb potential. In 1966, Fisher and Ruelle have in [14] raised the important question of the stability of many-particle systems...

The modified Newtonian dynamics (MOND) has been proposed as an alternative to the dark matter paradigm; the philosophy behind is that there is no dark matter and we witness a violation of the Newtonian law of dynamics. In this Letter, we interpret differently the phenomenology sustaining MOND, as resulting from an effect of “gravitational polarization”, of some cosmic fluid made of dipole momen...