Related papers: Particle decays during the cosmic dark ages
The cosmological vacuum decay scenario recently proposed by Wang and Meng \cite{wm} is rediscussed. From thermodynamic arguments it is found that the $\epsilon$ parameter quantifying the vacuum decay rate must be positive in the presence of…
Multidimensional modification of gravity with a smaller mass scale of the gravitational interaction is considered. Stable by assumption dark matter particles could decay via interactions with virtual black holes. The decay rates of such…
The power spectrum of fluctuations in the cosmic microwave background (CMB) depends on most of the key cosmological parameters. Accurate future measurements of this power spectrum might therefore allow us to determine h, Omega, Omega_b,…
Despite evidence for the existence of dark matter (DM) from very high and low redshifts, a moderate amount of DM particle decay remains a valid possibility. This includes both models with very long-lived yet unstable particles or mixed…
We propose a new class of metastable dark energy (DE) phenomenological models in which the DE decay rate does not depend on external parameters such as the scale factor or the curvature of the Universe. Instead, the DE decay rate is assumed…
When the Dark Matter mass is below the eV-scale, its cosmological occupation number exceeds the ones of photons from the cosmic microwave background as well as of relic neutrinos. If such Dark Matter decays to pairs of neutrinos, it implies…
This paper follows "The physics and identity of Dark Energy", which is the acceleration energy of old photons. The present paper considers everything else in the decay of our universe; it is an ensemble called "old protons, etc."; the…
We use lookback time versus redshift data from galaxy clusters (Capozziello et al., 2004) and passively evolving galaxies (Simon et al., 2005), and apply a bayesian prior on the total age of the Universe based on WMAP measurements, to…
Unparticle cosmology gives an unconventional outlook on the dark sector of cosmology, increasingly challenging $\Lambda\mbox{CDM}$ by $H_0$-tension. This model derives from a finite temperature broken conformal symmetry of radiation,…
An initial state for the observable universe consisting of a finite region with a large vacuum energy will break-up due to near horizon quantum critical fluctuations. This will lead to a Friedmann-like early universe consisting of an…
We explore some basic observational consequences of assuming that the dark matter in the Milky Way consists mainly of molecular clouds, and that cosmic rays can penetrate these clouds. In a favoured model of the clouds, this penetration…
We study the imprint of a coupling of scalar dark energy to photon on the cosmic microwave background (CMB) polarization. The time-evolving field value as well as the perturbation of the scalar generically induce $B$-mode polarization.…
After inflation the Universe presumably undergoes a phase of reheating which in effect starts the thermal big bang cosmology. However, so far we have very little direct experimental or observational evidence of this important phase of the…
Injection of high energy electromagnetic particles around the recombination epoch can modify the standard recombination history and therefore the CMB anisotropy power spectrum. Previous studies have put strong constraints on the amount of…
In currently popular cosmological scenarios -- all variants of the cold dark matter (CDM) cosmogony -- some time beyond a redshift of 15, stars within the numerous small halos that condense with virial temperatures ~1e4 K created the first…
It is assumed that the dark energy observed today is frozen as a result of a phase transition involving the source of that energy. Postulating that the dark energy de-coherence which results from this phase transition drives statistical…
The influence of dark matter particle decay on the baryon-to-photon ratio has been studied for different cosmological epochs. We consider different parameter values of dark matter particles such as mass, lifetime, the relative fraction of…
Among the several strategies for indirect searches of dark matter, one very promising one is to look for the gamma-rays from decaying dark matter. Here we use the most up-to-date upper bounds on the gamma-ray flux from $10^5$ to $10^{11}$…
Dark matter annihilation or decay could have a significant impact on the ionisation and thermal history of the universe. In this paper, we study the potential contribution of dark matter annihilation (s-wave- or p-wave-dominated) or decay…
The presence of dark energy in the Universe is inferred directly from the accelerated expansion of the Universe, and indirectly, from measurements of cosmic microwave background (CMB) anisotropy. Dark energy contributes about 2/3 of the…