Related papers: Massive Particle Decay and Cold Dark Matter Abunda…
We show that hidden hot dark matter, hidden-sector dark matter with interactions that decouple when it is relativistic, is a viable dark matter candidate provided it has never been in thermal equilibrium with the particles of the standard…
We study general freeze-out scenarios where an arbitrary number of initial and final dark matter particles participate in the number-changing freeze-out interaction. We consider a simple sector with two particle species undergoing such a…
We examine the thermal evolution of particle number densities in the early universe when the particles have a finite diffusion length. Assuming that annihilations are impossible when the mean separation of the particles is larger than their…
In standard cosmological scenarios, a heavy meta-stable field dominates the energy density of the universe after inflation. The dissipation of this field continuously sources high-energy particles. In general, the dissipation rate of this…
We investigate dark matter (DM) production in an early matter dominated era where a heavy long-lived particle decays to radiation and DM. In addition to DM annihilation into and thermal DM production from radiation, we include direct DM…
Recent cosmological data allow to determine the universal Dark Matter (DM) density to a precision of about 10%, if a simple, well-motivated ansatz for the spectrum of primordial density perturbations is correct. Not surprisingly, a thermal…
There is plenty of evidence that most matter in the Universe is dark (non-luminous). Particle physics offers several possible explanations. In this talk I focus on cold dark matter; the most promising candidates are then axions and the…
Assuming that (1) the universe underwent a post-inflationary accelerated expansion phase driven by a fluid with equation of state $P=w\rho$ and $-1<w<-1/3$, that (2) the cosmic horizon in an accelerating, quasi-de Sitter universe has a…
Atomic dark matter is usually considered to be produced asymmetrically in the early Universe. In this work, we first propose that the symmetric atomic dark matter can be thermally produced through the freeze-out mechanism. The dominant atom…
Dark Matter relic density generation through \textit{freeze-in} mechanism where dark matter particles interact feebly with visible sector particles, is an alternative approach to well-studied and most popular \textit{freeze-out} paradigm.…
Dark matter may be hidden, with no standard model gauge interactions. At the same time, in WIMPless models with hidden matter masses proportional to hidden gauge couplings squared, the hidden dark matter's thermal relic density may…
Big Bang nucleosynthesis in the presence of decaying relic neutral particles is examined in detail. All non-thermal processes important for the determination of light-element abundance yields of 2H, 3H, 3He, 4He, 6Li, and 7Li are coupled to…
The simplest cosmologies motivate the consideration of dark matter subcomponents that interact significantly with normal matter. Moreover, such strongly-coupled relics may have evaded detection to date if upon encountering the Earth they…
We explore a class of dark matter models with two dark matter candidates, only one interacts with the standard model sector. One of the dark matter is thermalized with the assistance of the other stable particle. While both stable particles…
In a non-standard cosmological scenario, heavy, long-lived particles, which we call moduli, dominate the energy density prior to Big Bang Nucleosynthesis. Weakly Interacting Massive Particles (WIMPs) may be produced non-thermally from…
Supersymmetry can explain the observed dark matter relic density with a neutralino dark matter particle and a coannihilating, almost mass-degenerate sparticle. If this were the case in nature, a linear electron positron collider like the…
We demonstrate that if the universe is dominated by the massive cold dark matter, then besides the generally believed thermal distribution of the dark matter relics, there may exist some very energetic non-thermal relics of the dark matter…
The standard theoretical estimation of the thermal dark matter abundance may be significantly altered if properties of dark matter particles in the early universe and at the present cosmological epoch differ. This may happen if, e.g., a…
If the energy density of the Universe before nucleosynthesis is dominated by a scalar field phi that decays and reheats the plasma to a temperature T_{RH} smaller than the standard neutralino freeze out temperature, the neutralino relic…
A larger Planck scale during an early epoch leads to a smaller Hubble rate, which is the measure for efficiency of primordial processes. The resulting slower cosmic tempo can accommodate alternative cosmological histories. We consider this…