Related papers: Neutrinos as Dark Matter
The nature of dark matter is one of the open problems of the Standard Model of particle physics. Despite the great experimental efforts, we have not yet found a positive signal of its interactions with ordinary matter. One possible…
The Keplerian distribution of velocities is not observed in the rotation of large scale structures, such as found in the rotation of spiral galaxies. The deviation from Keplerian distribution provides compelling evidence of the presence of…
The super-weak model is a U(1) extension of the Standard Model. In addition to a mediator $Z'$, a singlet scalar field $\chi$ is added to deal with the meta-stability of the SM vacuum, and right-handed neutrinos are introduced to account…
Despite the astonishing success of standard $\Lambda$CDM cosmology, there is mounting evidence for a tension with observations at small and intermediate scales. We introduce a simple model where both cold dark matter (DM) and sterile…
Dark matter (DM) annihilations in the Galaxy may produce high energy neutrinos, which can be detected by the neutrino telescopes, for example IceCube, ANTARES and Super-Kamiokande. The neutrinos can also arise from hadronic interaction…
We investigate observable cosmological aspects of sterile neutrino dark matter produced via the freeze-in mechanism. The study is performed in a framework that admits many cosmologically interesting variations: high temperature production…
Using several cosmological observations, i.e. the cosmic microwave background anisotropies (WMAP), the weak gravitational lensing (CFHTLS), the measurements of baryon acoustic oscillations (SDSS+WiggleZ), the most recent observational…
Cosmology at present provides the nominally strongest constraint on the masses of standard model neutrinos. However, this constraint extremely dependent on the nature of the dark energy component of the Universe. When the dark energy…
We apply phase-space density considerations to obtain lower bounds on the mass of sterile neutrino as dark matter candidate. The bounds are different for non-resonant production, resonant production in the presence of lepton asymmetry and…
We explore a novel possibility that dark matter has a light mass below 1GeV in a lepton portal dark matter model. There are Yukawa couplings involving dark matter, left-handed leptons and an extra scalar doublet in the model. In the light…
We present an updated analysis of the constrained minimal supersymmetric standard model with mu>0 supplemented by an `asymptotic' Yukawa coupling quasi-unification condition, which allows an acceptable b-quark mass. Imposing constraints…
We consider the singlet Majoron model with softly broken lepton number. This model contains three right-handed neutrinos and a singlet scalar besides the standard model fields. The real part of the singlet scalar develops a vacuum…
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)…
Search for the neutrino mass and for cold dark matter in the Universe are at present two of the most exciting fields of particle physics and cosmology. This lecture will restrict itself on the search for neutralinos as cold dark matter, and…
A neutrino mass model is suggested within an $SU(4)\times U(1)$ -- electroweak theory. The smallness of neutrino masses can be guaranteed by a seesaw mechanism realized through Yukawa couplings to a scalar $SU(4)$-decuplet. In this scheme…
We investigate whether interaction between massive neutrinos and quintessence scalar field is the origin of the late time accelerated expansion of the universe. We present explicit formulas of the cosmological linear perturbation theory in…
There exist field theory models where the fermionic energy-momentum tensor contains a term proportional to g_{\mu\nu}\bar{\Psi}\Psi which can be responsible for a dark matter to dark energy transmutation. We study some cosmological aspects…
We review theoretically well-motivated dark-matter candidates, and pathways to their discovery, in the light of recent results from collider physics, astrophysics, and cosmology. Taken in aggregate, these encourage broader thinking in…
We now know firmly that neutrinos have tiny masses, but in the minimal Standard Model there is no natural sources for such tiny masses. On the other hand, the extra heavy Z^{\prime 0} requires the extra Higgs field, the particle generating…
Interest in light dark matter candidates has recently increased in the literature; some of these works consider the role of additional neutrinos, either active or sterile. Furthermore, extragalactic neutrinos have been detected with…