Related papers: Mass-Varying Neutrinos from a Variable Cosmologica…
We present a theory of neutrino oscillations in a dense medium which goes beyond the effective matter potential used in the description of the MSW effect. We show how the purity of the neutrino state is degraded by neutrino interactions…
We consider an extended seesaw model which generates active neutrino masses via the usual type-I seesaw and leads to a large number of massless fermions as well as a sterile neutrino dark matter (DM) candidate in the $\mathcal{O}(10-100)…
Recently, it has been shown that cosmic neutrino flux at the GRB/AGN source, $F_{\nu_e}^0 : F_{\nu_{\mu}}^0 : F_{\nu_{\tau}}^0 \simeq 1 :2 :0 $, inevitably oscillates (in the three neutrino framework) to 1 : 1: 1, irrespective of the mixing…
A puzzling implication of current data interpreted in the $\Lambda$CDM cosmology is the preference for a negative sum of neutrino masses. Moving to $w_0w_a$CDM brings an appreciable fraction of the neutrino mass posterior back to positive…
Cosmic voids offer an extraordinary opportunity to study the effects of massive neutrinos on cosmological scales. Because they are freely streaming, neutrinos can penetrate the interior of voids more easily than cold dark matter or baryons,…
Recently, DESI has released baryon acoustic oscillation (BAO) data, and DES has also published its five-year supernova (SN) data. These observations, combined with cosmic microwave background (CMB) data, support a dynamically evolving dark…
We thoroughly explore the cosmic gravitational focusing of cosmic neutrino fluid (C$\nu$F) by dark matter (DM) halo using both general relativity for a point source of gravitational potential and Boltzmann equations for continuous…
A revolution in our understanding of the neutrino sector is underway, driven by observations that are interpreted in terms of changes in neutrino flavors as they propagate. Since neutrino oscillations occur only if neutrinos are massive,…
The seesaw mechanism is conceived on the basis that a mass scale, $\xi$, and a dimensionless scale, $s$, can be fine-tuned in order to control the dynamics of active and sterile neutrinos through cosmon-type equations of motion: the seesaw…
Growing neutrino quintessence solves the coincidence problem for dark energy by a growing cosmological value of the neutrino mass which emerges from a cosmon-neutrino interaction stronger than gravity. The cosmon-mediated attraction between…
The widely accepted description of the present cosmic acceleration and the neutrino oscillations in terms of a cosmological constant and neutrino masses, respectively, seems conceptually not very satisfactory. From a phenomenological…
Recent observations of the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO) show some tension with a $\Lambda$CDM cosmology. For one, the cosmological parameters determined by the CMB are at odds with the expansion…
It has been suggested that Einstein's theory of General Relativity can be modified to accomodate mismatches between the gravitational field and luminous matter on a wide range of scales. Covariant theories of modified gravity generically…
The bulk of recent cosmological research has focused on the adiabatic cold dark matter model and its simple extensions. Here we present an accurate fitting formula that describes the matter transfer functions of all common variants,…
The mechanism for generating neutrino masses remains a puzzle in particle physics. If neutrino masses follow from a Dirac mass term, then neutrino states exist with opposite chirality compared to their weakly-interacting counterparts. These…
There is a puzzling contradiction: direct observations favor a low-mass density universe, but the only model which fits universe structure over more than three orders of magnitude in distance scale has a mix of hot (neutrino) and cold dark…
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…
The cosmological Mass Varying Neutrino (MaVaN) model is considered, where the interaction between a fermionic field and a scalar field with a Ratra-Peebles potential via a Yukawa coupling is investigated. Observational constraints on the…
A key question in cosmology is whether massive neutrinos exist on cosmic scales. Current cosmological observations have severely compressed the viable range for neutrino masses and even prefer phenomenologically an effective negative mass.…
Cosmological parameter estimation exercises usually make the approximation that the three standard neutrinos have degenerate mass, which is at odds with recent terrestrial measurements of the difference in the square of neutrino masses. In…