Related papers: Derivation of the sterile neutrino Boltzmann equat…
Some evidence for sterile neutrinos has been found in short baseline observations where the measured neutrino flux did not agree with expectations. Systematic uncertainties from the expected values has limited the sensitivity of this…
Explicit expressions for the differential and total rates and emissivities of neutrino pairs from the photo-neutrino process $e^\pm + \gamma \to e^\pm + \nu + \bar\nu$ in hot and dense matter are derived. Full information about the emitted…
Understanding how new physics influences the dynamics of cosmic neutrinos during their decoupling is crucial in light of upcoming precise cosmological observations and the need to reconcile cosmological and laboratory probes. Existing…
Phenomenology of neutrino oscillations in vacuum and in cosmological plasma is considered. Neutrino oscillations in vacuum are usually described in plane wave approximation. In this formalism there is an ambiguity if one should assume…
Sterile neutrinos with masses in the keV range are considered to be a viable candidate for warm dark matter. The rate of their production through active-sterile neutrino transitions peaks, however, at temperatures of the order of the QCD…
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…
We develop a general and consistent model of neutrino oscillation based on the quantum field theoretical description of the neutrino production and detection processes. Emphasis is placed on the locality of the interactions of these…
We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the…
Neutrino scillations cannot arise from an initial isolated one particle state if four-momentum is conserved. The transition matrix element is generally squared and summed over all final states with no interference between orthogonal final…
We study the dynamics of active-sterile neutrino oscillations in the early universe using full momentum-dependent quantum-kinetic equations. These equations are too complicated to allow for an analytical treatment, and numerical solution is…
In this paper, we analyze in a mathematically rigorous fashion the validity of the Boltzmann transport equation within quantum field theory. We work within the specific model of a hermitian, scalar field with polynomial self-interaction in…
The existence of light sterile neutrinos is a long standing question for particle physics. Several experimental ``anomalies'' could be explained by introducing ~eV mass scaled light sterile neutrinos. Many experiments are actively hunting…
The data on atmospheric neutrinos can be explained assuming the existence of oscillations between muon neutrinos and light sterile neutrinos with mixing close to maximal, and Delta_m^2 approximately equal to 3 E-3 (eV^2). This…
A new density matrix and corresponding quantum kinetic equations are introduced for fermions undergoing coherent evolution either in time (coherent particle production) or in space (quantum reflection). A central element in our derivation…
After the recent experimental results on neutrino oscillations, some shape starts to emerge from the puzzle. However, the situation is still far from being clarified. First of all, accommodating all experimental results in a single and…
The exact Quantum Kinetic Equations for a two-flavour active-sterile neutrino system are used to provide a systematic derivation of approximate evolution equations for the relic neutrino asymmetry. An extension of the adiabatic…
We perform a detailed study of the weak interactions of standard model neutrinos with the primordial plasma and their effect on the resonant production of sterile neutrino dark matter. Motivated by issues in cosmological structure formation…
Light sterile neutrinos represent a well-motivated extension of the 3-neutrino paradigm. However, the impressive agreement between standard cosmology and data casts doubts on their existence. Here we present a class of scenarios that…
We derive the neutrino oscillation probabilities including sterile neutrinos by using the Dirac equation. If neutrinos have both the Dirac and the Majorana mass terms, left-handed neutrino $\nu_L$ and right-handed anti-neutrino $\nu_R^c$…
We discuss the excitation of sterile neutrinos in the early universe using general quantum kinetic equations, which also incorporate a possible primordial magnetic field $B$. We find a new contribution to the excitation propability, which…