相关论文: Is Cold Dark Matter Baryonic? Alternative Opinion

If the dark matter is produced in the early universe prior to Big Bang nucleosynthesis, a modified cosmological history can drastically affect the abundance of relic dark matter particles. Here, we assume that an additional species to…

I present an overview of some of the recent advances in our understanding of the distribution and evolution of the ordinary, baryonic matter in the universe. Two observations that strongly suggest that most of the baryons seen at high…

A light higgsino is strongly favored by the naturalness, while as a dark matter candidate it is usually under-abundant. We consider the higgsino production in a non-standard history of the universe, caused by a scalar field with an…

Following a brief introduction to early Universe cosmology, the current of status of big bang nucleosynthesis is reviewed and the concordance between theory and observation is examined in detail. The abundances of He4 and Li7 determine the…

We discuss an overlooked factor in dark matter studies. Namely, if massless particles are captured into a local structure and stop free streaming in the universe, they no longer lose energy by cosmological red-shift, and no longer smear out…

In cosmological models favored by current observations, the first astrophysical objects formed in dark matter halos at redshifts starting at z>20, and their properties were determined by primordial H_2 molecular chemistry. These…

We investigate Big Bang nucleosynthesis (hereafter, BBN) in a cosmic environment characterized by a distribution of small-scale matter/antimatter domains. Production of antimatter domains in a baryo-asymmetric universe is predicted in some…

High energy collisions of particles may have created tiny black holes in the early Universe, which might leave stable remnants instead of fully evaporating as a result of Hawking radiation. If the reheating temperature was sufficiently…

Many independent high resolution simulations have indicated that the standard collisionless cold dark matter model does not reproduce the structure of observed present day galaxies well. Several possible solutions in the form of…

The nature of the dark matter in the halo of our Galaxy is still largely unknown. The microlensing events found so far towards the Large Magellanic Cloud suggest that at most about 20% of the halo dark matter is in the form of MACHOs…

As is well known, most of the baryons are observationally unaccounted. Moreover, certain recent developments suggest that dark baryons are mostly locked up in galactic halos - which are anyway dominated by nonbaryonic dark matter - and a…

New, high resolution, large-scale, cosmological hydrodynamic galaxy formation simulations of a standard cold dark matter model (with a cosmological constant) are utilized to predict the distribution of baryons at the present and at moderate…

A straightforward interpretation of the MACHO microlensing results in the direction of the Magellanic Clouds suggests that an important fraction of the baryonic dark matter component of our Galaxy is in the form of old white dwarfs. If…

One of the great scientific enigmas still unsolved, the existence of dark matter, is reviewed. Simple gravitational arguments imply that most of the mass in the Universe, at least 90%, is some (unknown) non-luminous matter. Some particle…

The possibility that dark matter particles could be constituted by extreme regular primordial black holes is discussed. Extreme black holes have zero surface temperature, and are not subjected to the Hawking evaporation process. Assuming…

An abundance of astrophysical evidence indicates that the bulk of matter in the universe is made up of massive, electrically neutral particles that form the dark matter (DM). While the density of DM has been precisely measured, the identity…

It is proposed that dark matter could consist of compressed collections of atoms (or metallic matter) encapsulated into, for example, 20 cm big pieces of a different phase. The idea is based on the assumption that there exists at least one…

Sterile neutrinos with keV masses can constitute all or part of the cosmological dark matter. The electroweak-singlet fermions, which are usually introduced to explain the masses of active neutrinos, need not be heavier than the electroweak…

The hot dense environment of the early universe is known to have produced large numbers of baryons, photons, and neutrinos. These extreme conditions may have also produced other long-lived species, including new light particles (such as…

Observations show that about the 20% of the Universe is composed by invisible (dark) matter (DM), for which many candidates have been proposed. In particular, the anomalous behavior of rotational curves of galaxies (i.e. the flattening at…