0000000000113210
AUTHOR
Marija Kekic
showing 2 related works from this author
Phenomenology of low-scale Seesaw Models
2016
All the observed particles are well accommodated in the Standard Model, together with the basic forces. However, there are both experimental and theoretical hints that the Standard Model can not be a complete theory and that New Physics is needed. Some of the theoretical problems are: i) The flavor-puzzle, i.e., why are there three copies of particles differing only by their mass. Most of the free parameters in the Standard Model are linked to this puzzle. They have been measured, but their values do not follow any clear pattern and their origin remains elusive. ii) The strong CP problem, that is, why the CP symmetry is conserved in the strong interactions in the Standard Model, which is no…
Neff versus the lightest neutrino mass
2016
AbstractWithin the framework of low-scale Type I seesaw models with two and three extra sterile neutrinos we evaluate the production of the sterile states in the Early Universe. We explore the full parameter space and find that in the model with two extra states both of them reach thermal equilibrium with the primordial plasma. In the model with three sterile neutrinos, if the lightest active neutrino mass is below O(10−3eV) one sterile neutrino might not thermalize, while the other two always reach thermalization. Applying constrains from both extra radiation at BBN and CMB, and the dark matter allowed abundance, we show that the spectra of heavier states are severely restricted in the mas…