相关论文: Cosmological Signatures of Superheavy Dark Matter

We investigate density fluctuations in a scenario with gravitino dark matter in the framework of modulated reheating, which is known to generate large non-Gaussianity. We show that gravitino dark matter is disfavored if primordial…

Motivated by their potential role as dark matter, we study the cosmological evolution of light scalar and vector fields non-minimally coupled to gravity. Our focus is on a situation where the dominant contribution to the energy density…

Primordial non-Gaussianity signatures of extremely heavy particles are re-examined within a simple alternative to the standard inflationary paradigm, in which the primordial fluctuations and the inflationary spacetime expansion are sourced…

We show that gravitinos produced by decays of a supersymmetry breaking scalar field (the pseudo-moduli field) can naturally explain the observed abundance of dark matter in a certain class of the gauge mediation models. We study the decay…

Dark matter could have an electroweak origin, yet communicate with the visible sector exclusively through gravitational interactions. In a set-up addressing the hierarchy problem, we propose a new dark matter scenario where gravitational…

Gravitinos and hidden sector fields often cause a cosmological disaster in supersymmetric models. We find that a model with gravitational gauge mediation solves such a problem quite naturally. The mu-problem is also absent in the model.…

We study in detail the recently proposed mechanism of generating superheavy Dark Matter with the mass larger than the Hubble rate at the end of inflation. A real scalar field constituting Dark Matter linearly couples to the inflaton. As a…

We consider the astrophysical bounds on a new form of dark matter, the so called Gravity-mediated Dark Matter. In this scenario, dark matter communicates with us through a mediator sector composed of gravitational resonances, namely a new…

We investigate primordial non-Gaussianity and dark matter isocurvature fluctuations in the modulated reheating and the curvaton scenarios. In these scenarios, large non-Gaussianity can be generated, on the other hand, depending on how dark…

Since a positive future detection of non-linearity in the cosmic microwave background anisotropy pattern might allow to descriminate among different mechanisms giving rise to cosmological adiabatic perturbations, we study the evolution of…

Dark matter caustics have specific density profiles and, therefore, precisely calculable gravitational lensing properties. We present a formalism which simplifies the relevant calculations, and apply it to four specific cases. In the first…

We study density perturbations, including their non-Gaussianity, in models in which the decay rate of the curvaton depends on another light scalar field, denoted the modulaton. Although this model shares some similarities with the standard…

In this work, we review a plethora of modified theories of gravity with generalized curvature-matter couplings. The explicit nonminimal couplings, for instance, between an arbitrary function of the scalar curvature $R$ and the Lagrangian…

Cosmological evolution and particle creation in $R^2$-modified gravity are considered for the case of the dominant decay of the scalaron into a pair of gauge bosons due to conformal anomaly. It is shown that in the process of thermalization…

In this study one resorts to the phenomenology of models endowed with a non-minimal coupling between matter and geometry, in order to develop a mechanism through which dynamics similar to that due to the presence of dark matter is…

Little is known about dark matter beyond the fact that it does not interact with the standard model or itself, or else does so incredibly weakly. A natural candidate, given the history of no-go theorems against their interactions, are…

We investigate the cosmological implications of a new class of modified gravity, where the field equations generically include higher-order derivatives of the matter fields, arising from the introduction of non-dynamical auxiliary fields in…

We propose a cosmological dark matter production mechanism in the form of a longitudinal massive vector boson. We build upon the work of Graham et.al. including non-minimal couplings of the massive vector with gravity, developing a well…

Non-minimal couplings between matter and curvature tensors arise in many different contexts. Such couplings modify solutions of general relativity (GR) and therefore can be probed in various astrophysical systems. A particularly interesting…

Dark matter may be coupled to dark radiation: light degrees of freedom that mediate forces between dark sector particles. Cosmological constraints favor dark radiation that is colder than Standard Model radiation. In models with fixed…