Related papers: MeV-scale Reheating Temperature and Thermalization…
We investigate cosmological effects concerning the late-time entropy production due to the decay of non-relativistic massive particles. The thermalization process of neutrinos after the entropy production is properly solved by using the…
Small Recent theories have proposed a variety of massive particles, like the moduli, whose abundance or decay endangers standard cosmological results. To dilute them, thermal inflation has been proposed, with its own massive scalar flaton…
From a theoretical point of view, there is a strong motivation to consider an MeV-scale reheating temperature induced by long-lived massive particles with masses around the weak scale, decaying only through gravitational interaction. In…
We investigate how sterile neutrinos with a range of masses influence cosmology in MeV-scale reheating temperature scenarios. By computing the production of sterile neutrinos through the combination of mixing and scattering in the early…
Entropy production from scalar decay in the era of low temperatures after neutrino decoupling will change the ratio of the relic neutrino temperature to the CMB temperature, and, hence, the value of N_eff, the effective number of neutrino…
We consider relatively heavy neutrinos $\nu_H$, mostly contributing to a sterile state $\nu_s$, with mass in the range 10 MeV $\lesssim m_s \lesssim m_{\pi} \sim 135$ MeV, which are thermally produced in the early universe in collisional…
Late-time entropy production from scalar decay arises in scenarios like thermal inflation, proposed to dilute long-lived, massive fields like the gravitino and the moduli. The scalar decay may continue into Mev-scale temperatures and affect…
Neutrino physics in the early Universe is key to our understanding of later cosmological stages, such as primordial nucleosynthesis (BBN) or the formation of large-scale structures. The coming decade promises new experimental results to…
It is commonly assumed that the cosmological and astrophysical bounds on the mixings of sterile with active neutrinos are much more stringent than those obtained from laboratory measurements. We point out that in scenarios with a very low…
Light dark-matter ($M\leq20$ MeV) particles freeze out after neutrino decoupling. If the dark-matter particle couples to a neutrino or an electromagnetic plasma, the late time entropy production from dark-matter annihilation can change the…
We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy. We show that neutrinos can begin to decouple at higher temperatures than previous estimates due to several corrections…
We study how the oscillations of the neutrinos affect their thermalization process during the reheating period with temperature O(1) MeV in the early universe. We follow the evolution of the neutrino density matrices and investigate how the…
The connection between cosmological observations and neutrino physics is discussed in detail. Neutrinos decouple from thermal contact in the early Universe at a temperature of order 1 MeV which coincides with the temperature where light…
Sterile neutrinos produced through oscillations are a well motivated dark matter candidate, but recent constraints from observations have ruled out most of the parameter space. We analyze the impact of new interactions on the evolution of…
Leading finite temperature effects on the neutrino decoupling temperature in the early Universe have been studied. We have incorporated modifications of the dispersion relation and the phase space distribution due to the presence of…
We study the possibility to produce a keV neutrino dark matter candidate through the two-body decays of heavy neutrinos present in TeV scale neutrino mass generation mechanism. Given that the dark matter production happens at the heavy…
The origin of the hot phase of the early universe remains so far an unsolved puzzle. A viable option is entropy production through the decays of heavy Majorana neutrinos whose lifetimes determine the initial temperature. We show that…
We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range,…
Entropy changes due to delocalization and decoherence effects should modify the predictions for the cosmological neutrino background (C$\nu$B) temperature when one treats neutrino flavors in the framework of composite quantum systems.…
Interactions of heavy Majorana neutrinos in the thermal phase of the early universe may be the origin of the cosmological matter-antimatter asymmetry. This mechanism of baryogenesis implies stringent constraints on light and heavy Majorana…