Related papers: Additional Light Sterile Neutrinos and Cosmology
Sterile neutrinos with various masses could be participated in astrophysical and cosmological processes including mixing with active neutrinos, if exist. It is considered the possible effects of mixing of active and sterile neutrinos with…
We present cosmological constraints on the sum of neutrino masses as a function of the neutrino lifetime, in a framework in which neutrinos decay into dark radiation after becoming non-relativistic. We find that in this regime the cosmic…
We show that, in the presence of bulk masses, sterile neutrinos propagating in large extra dimensions (LED) can induce electron-neutrino appearance effects. This is in contrast to what happens in the standard LED scenario and hence LED…
Current measurements of the low and high redshift Universe are in tension if we restrict ourselves to the standard six parameter model of flat $\Lambda$CDM. This tension has two parts. First, the Planck satellite data suggest a higher…
Present cosmological observations yield an upper bound on the neutrino mass which is significantly stronger than laboratory bounds. However, the exact value of the cosmological bound is model dependent and therefore less robust. Here, I…
We add a singlet right handed neutrino plus a charged and a neutral singlet scalars to the standard model. This extension includes a discrete symmetry such that we obtain a heavy sterile neutrino which couples only to the electron and the…
Within the framework of the Standard Model of particle physics and standard cosmology, observations of the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO) set stringent bounds on the sum of the masses of neutrinos.…
The Phenomenologically Emergent Dark Energy model, a dark energy model with the same number of free parameters as the flat $\Lambda$CDM, has been proposed as a working example of a minimal model which can avoid the current cosmological…
Despite direct observations favoring a low mass density, a critical density universe with a neutrino component of dark matter provides the best existing model to explain the observed structure of the universe over more than three orders of…
Neutrinos play prominent roles in both particle physics and cosmology. In this talk, I will cover two broad topics. The first will be possible origins for neutrino masses and mixings and the implications of this physics for cosmology. Some…
We present new Big Bang Nucleosynthesis (BBN) limits on the cosmic expansion rate or relativistic energy density, quantified via the number $N_\nu$ of equivalent neutrino species. We use the latest light element observations, neutron mean…
Deviations from unitarity in the three-neutrino mixing canonical picture are expected in many physics scenarios beyond the Standard Model. The mixing of new heavy neutral leptons with the three light neutrinos would in principle modify the…
Neutrinos, being the only fermions in the Standard Model of Particle Physics that do not possess electromagnetic or color charges, have the unique opportunity to communicate with fermions outside the Standard Model through mass mixing. Such…
For a long time there were 3 main experimental indications in favor of the existence of sterile neutrinos: $\bar{\nu_e}$ appearance in the $\bar{\nu_\mu}$ beam in the LSND experiment, $\bar{\nu_e}$ flux deficit in comparison with…
Sterile neutrino dark matter, a popular alternative to the WIMP paradigm, has generally been studied in non-supersymmetric setups. If the underlying theory is supersymmetric, we find that several interesting and novel dark matter features…
Neutrinos are one of the major puzzles in modern physics. Despite measurements of mass differences, the Standard Model of particle physics describes them as exactly massless. Additionally, recent measurements from both particle physics…
We propose signals in the cosmic microwave background to probe the type and spectrum of neutrino masses. In theories that have spontaneous breaking of approximate lepton flavor symmetries at or below the weak scale, light pseudo-Goldstone…
Considering the gauge model SU(2)_L x U(1) with the extension of the lepton sector by right-handed sterile Majorana neutrinos, we distinguish a "minimal parametric mixing scenario" for a complete matrix of 6 x 6 light (active) and sterile…
In the framework of a 3+1 scheme with an additional inert state, we consider the thermalisation of sterile neutrinos in the early Universe taking into account the full $4\times4$ mixing matrix. The evolution of the neutrino energy…
Sterile neutrinos are possible dark matter candidates. We examine here possible detection mechanisms, assuming that the neutrino has a mass of about 50 keV and couples to the ordinary neutrino. Even though this neutrino is quite heavy, it…