Related papers: Changes in Dark Matter Properties After Freeze-Out
Thermal freeze-out is a prominent example of dark matter (DM) production mechanism in the early Universe that can yield the correct relic density of stable weakly interacting massive particles (WIMPs). At the other end of the mass scale,…
We consider a model of dark matter where the mediator corresponds to a superposition of a scalar and pseudoscalar, and the scenario where, after reheating, the number densities of the dark sector particles, i.e. the dark matter and the…
If supersymmetry exists at any scale, regardless of whether it is restored around the weak scale, it may be a good symmetry of the dark sector, enforcing a degeneracy between its lowest lying fermions and bosons. We explore the implications…
The observed dark matter relic abundance may be explained by different mechanisms, such as thermal freeze-out/freeze-in, with one or more symmetric/asymmetric components. In this work we investigate the role played by asymmetries in…
Kinetic decoupling of dark matter typically happens much later than chemical freeze-out. In fact, local thermal equilibrium is an important assumption for the usual relic density calculations based on solving the Boltzmann equation (for its…
We revisit dark-matter production through freeze-in and freeze-out by solving the Boltzmann equations at the level of the phase-space distribution $f(p,t)$. Using the $2\to2$ annihilation and the $1\to2$ decay processes for illustration, we…
If dark matter (DM) annihilation accounts for the tantalizing excess of cosmic ray electron/positrons, as reported by the PAMELA, ATIC, HESS and FERMI observatories, then the implied annihilation cross section must be relatively large. This…
We explore freezing dark energy, where the evolution of the field approaches that of a cosmological constant at late times. We propose two general, two parameter forms to describe the class of freezing field models, in analogy to ones for…
The dark-matter candidates of particle physics invariably possess electromagnetic interactions, if only via quantum fluctuations. Taken en masse, dark matter can thus engender an index of refraction which deviates from its vacuum value. Its…
A significant observational effort has been directed to unveil the nature of the so-called dark energy. However, given the large number of theoretical possibilities, it is possible that such a task cannot be performed on the basis only of…
A novel particle has been and still is an intriguing option to explain the strong evidence for dark matter in our universe. To quantitatively predict the dark matter energy density, two main ingredients are needed: interaction rates and an…
The fact that dark matter (DM), thus far, has revealed itself only on scales of galaxies and larger, again thrusts onto astrophysics the opportunity and the responsibility to confront the age old mystery "What is the nature of matter?" By…
We study the cooling of isolated dark-matter-admixed neutron stars, employing a realistic nuclear equation of state and realistic nuclear pairing gaps, together with fermionic dark matter of variable particle mass and dark-matter fraction.…
With the emersion of precise cosmology and the emergence of cosmic tensions, we are faced with the question of whether the simple model of cold dark matter needs to be extended and whether doing so can alleviate the tensions and improve our…
The thermal freeze-out mechanism in its classical form is tightly connected to physics beyond the Standard Model around the electroweak scale, which has been the target of enormous experimental efforts. In this work we study a dark matter…
In this paper, we calculate the relic abundance of the dark matter particles when they can annihilate into sterile neutrinos with the mass $\lesssim 100 \text{ GeV}$ in a simple model. Unlike the usual standard calculations, the sterile…
Well known scaling laws among the structural properties of the dark and the luminous matter in disc systems are too complex to be arisen by two inert components that just share the same gravitational field. This brings us to critically…
In the context of thermodynamics we discuss the way inevitable emerge an interaction between dark components, and in this way, provide a mechanism to understand the limits of the LCDM model and the class of interaction models between dark…
We study a novel dark matter production mechanism based on the freeze-in through semi-production, i.e. the inverse semi-annihilation processes. A peculiar feature of this scenario is that the production rate is suppressed by a small initial…
We study warm Higgs portal dark matter (DM) in the framework of freeze-in at stronger coupling. This scenario assumes that the Standard Model thermal bath temperature has always been relatively low, which suppresses dark matter production.…