相关论文: Avoiding BBN Constraints on Mirror Models for Ster…
A neutrino mass-mixing scheme which successfully avoids the "alpha effect," allowing r-process nucleosynthesis in the neutrino-heated ejecta of supernovae, quite independently requires the same parameters as the scheme which best fits all…
We investigate the implications of the standard Big-Bang Nucleosynthesis constraint on the number of light neutrinos in the framework of the two four-neutrino schemes that are favored by the results of neutrino oscillation experiments.
Recent cosmological data favour additional relativistic degrees of freedom beyond the three active neutrinos and photons, often referred to as 'dark' radiation. Light sterile neutrinos is one of the prime candidates for such additional…
String inspired models with millimeter scale extra dimensions provide a natural way to understand an ultralight sterile neutrino needed for a simultaneous explanation of the solar, atmospheric and LSND neutrino oscillation results. The…
Cosmological and astrophysical effects of heavy (10 - 200 MeV) sterile Dirac neutrinos, mixed with the active ones, are considered. The bounds on mass and mixing angle from both supernovae and big-bang nucleosynthesis are presented.
Cosmological measurements are affected by the energy density of both active and sterile massive neutrinos. We extend here a recent analysis of current cosmological data to non minimal cosmologies. Several possible scenarios are examined: a…
We investigate quantitatively the extent to which having a primordial leptonic asymmetry (n_nu \neq n_nubar) relaxes the bounds on light sterile neutrinos imposed by BBN and LSS. We adopt a few assumptions that allow us to solve the…
We analyze the oscillation signals generated by one extra sterile neutrino. We fully take into account the effects of the established oscillations among active neutrinos. We analyze the effects in solar, atmospheric, reactor and beam…
In this talk I discuss the use of a relic neutrino-antineutrino asymmetry in suppressing active-sterile neutrino oscillations in the early universe. This phenomenon can serve to greatly loosen the well known Big Bang Nucleosynthesis…
We discuss the possibility of sterile neutrinos taking shortcuts in extra dimensions, and the consequences for neutrino oscillations. This effect influences the active-sterile neutrino mixing and provides a possibility to accommodate the…
The existence of bulk sterile neutrinos in theories with large extra dimensions can naturally explain small 4-dimensional Dirac masses for the active neutrinos. We study a model with 3 bulk neutrinos and derive various constraints on the…
We discuss Big Bang Nucleosynthesis constraints on maximal $\nu_\mu\leftrightarrow\nu_s$ mixing. Vacuum $\nu_\mu\leftrightarrow\nu_s$ oscillation has been proposed as one possible explanation of the Super Kamiokande atmospheric neutrino…
Sterile neutrinos are a compelling candidate for generating neutrino masses and for elucidating the nature of dark matter. Astrophysical X-ray constraints on sterile neutrino dark matter decays, however, largely exclude the active-sterile…
Although the hypothetic sterile neutrino $\nu_s$ is probably not involved significantly in the deficits of solar $\nu_e$'s and atmospheric $\nu_\mu$'s, it may cause the possible LSND effect. In fact, we face such a situation, when the…
In this work we revisit the question of whether Cosmology can be made compatible with scenarios with light sterile neutrinos, as invoked to explain the SBL anomalies, in the presence of self-interaction among sterile neutrinos mediated by…
Tantalizing cosmological and terrestrial evidence suggests the number of light neutrinos may be greater than 3, motivating a careful re-examination of cosmological bounds on extra light species. Big Bang Nucleosynthesis constrains the…
The three massless active (doublet) neutrinos may mix with two heavy and one \underline {light} sterile (singlet) neutrinos so that the induced masses and mixings among the former are able to explain the present data on atmospheric and…
Precision cosmology and big-bang nucleosynthesis mildly favor extra radiation in the universe beyond photons and ordinary neutrinos, lending support to the existence of low-mass sterile neutrinos. We use the WMAP 7-year data, small-scale…
New experimental results, if correct, require at least one light sterile neutrino, in addition to the three active ones, to accommodate the mass differences required to explain the solar $\nu_e$ deficit, the anomalous $\nu/e$ ratio produced…
A particular form of mixing matrix for three active and one sterile neutrinos is proposed. Its $3\times 3 $ part describing three active neutrinos arises from the popular bimaximal mixing matrix that works satisfactorily in solar and…