Related papers: Is the CMB telling us that dark matter is weaker t…

Cosmological moduli generically come to dominate the energy density of the early universe, and thereby trigger an early matter dominated era. Such non-standard cosmological histories are expected to have profound effects on the evolution…

Decay of the inflaton or moduli which dominated the energy density of the universe at early times leads to a matter to radiation transition epoch. We consider non-thermal sterile dark matter particles produced as decay product during such…

The relic abundance of thermal dark matter particles is generally assumed to be inversely proportional to their annihilation rate, which is therefore constrained by the present matter density, <sigma v> ~ 10^{-26} Omega_{dm}^{-1} cm^3…

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…

Decaying cold dark matter (CDM) has been considered as a mechanism to tackle the tensions in the Hubble expansion rate and the clustering of matter. However, polarization measurements of the cosmic microwave background (CMB) severely…

Dark matter is a vital component of the current best model of our universe, $\Lambda$CDM. There are leading candidates for what the dark matter could be (e.g. weakly-interacting massive particles, or axions), but no compelling observational…

Dark Matter (DM) annihilation and decay during the Dark Ages can affect the cosmic ionization history and leave imprints in the Cosmic Microwave Background (CMB) anisotropy spectra. CMB polarization anisotropy can be sensitive to such…

Recent cosmological measurements favour additional relativistic energy density beyond the one provided by the three active neutrinos and photons of the Standard Model (SM). This is often referred to as "dark radiation", suggesting the need…

Weakly interacting massive particles (WIMPs) remain the strongest candidates for the dark matter in the Universe. If WIMPs are the dark matter, they will form galactic halos according to the hierarchical clustering observed in N-body…

Dark matter constitutes about $23\%$ of the total energy density of the universe but its properties are still little known besides that it should be composed by cold and weakly interacting particles. Many beyond standard model theories can…

Cosmologically long-lived, composite states arise as natural dark matter candidates in theories with a strongly interacting hidden sector at a scale of 10 - 100 TeV. Light axion-like states, with masses in the 1 MeV - 10 GeV range, are also…

We consider a self-interacting dark matter model in which the massive dark photon mediating the self-interaction decays to light dark fermions to avoid over-closing the universe. We find that if the model is constrained to explain the dark…

The cold dark matter may be in a meta-stable state and decays to other particles with a very long lifetime. If the decaying products of the dark matter are weakly interacting, e.g. neutrinos, then it would have little impact on…

We consider moduli fields interacting with thermalized relativistic matter. We determine the temperature dependence of their damping rate and find it is dominated by thermal effects in the high temperature regime, i.e. for temperatures…

Recently it was shown that dark matter with mass of order the weak scale can be charged under a new long-range force, decoupled from the Standard Model, with only weak constraints from early Universe cosmology. Here we consider the…

We consider particle decays during the cosmic dark ages with two aims: (1) to explain the high optical depth reported by WMAP, and (2) to provide new constraints to the parameter space for decaying particles. We delineate the decay channels…

We consider the production of axion dark matter through the misalignment mechanism in the context of a nonstandard cosmological history involving early matter domination by a scalar field with a time-dependent decay rate. In cases where the…

It is entirely possible that our Universe is filled with dark radiation, such as SM neutrinos or new physics states, that are sourced by the decay of dark matter with cosmologically long lifetime. If non-thermal neutrinos produced such way…

The generic expectation in string/supergravity models is that there are multiple moduli fields with masses of the order of the supersymmetry breaking scale. We study the cosmology that arises as a result of vacuum misalignment of these…

The supersymmetrized DFSZ axion model is especially compelling in that it contains 1. the SUSY solution to the gauge hierarchy problem, 2. the Peccei-Quinn (PQ) solution to the strong CP problem and 3. the Kim-Nilles solution to the SUSY mu…