Orateur
Dr
Alexander Kartavtsev
(Max-Planck Institut für Physik)
Description
We study the impact of TeV-scale sterile neutrinos on electro-weak precision observables and lepton number and flavour violating decays in the framework of a type-I see-saw extension of the Standard Model. At tree level sterile neutrinos manifest themselves via non-unitarity of the PMNS matrix and at one-loop level they modify the oblique radiative corrections. We derive explicit formulae for the S,T,U parameters in terms of the neutrino masses and mixings and perform a numerical fit to the electro-weak observables. We find regions of parameter space with a sizable active-sterile mixing which provide a better over-all fit compared to the case where the mixing is negligible. Specifically we find improvements of the invisible Z-decay width, the charged-to-neutral-current ratio for neutrino scattering experiments and of the deviation of the W boson mass from the theoretical expectation.
Auteur principal
Dr
Alexander Kartavtsev
(Max-Planck Institut für Physik)
Co-auteurs
Prof.
Evgeny Akhmedov
(Max-Planck-Institute for Nuclear Physics)
M.
Juri Smirnov
(Max-Planck-Institute for Nuclear Physics)
Mme
Lisa Michaels
(Max-Planck-Institute for Nuclear Physics)
Prof.
Manfred Lindner
(Max-Planck-Institute for Nuclear Physics)
