Effects of fermionic singlet neutrinos on high- and low-energy observables
type: Dataset
contact point: Organization
  fn: CCSD
keyword: modele-standard
keyword: supersymetrie
keyword: infoeu-reposemanticsdoctoralthesis
keyword: standard-model
keyword: seesaw-inverse
keyword: lepton-flavour-violation
keyword: violation-de-la-saveur-leptonique
keyword: neutrinos
keyword: inverse-seesaw
keyword: physcondcm-genphysics-physicscondensed-matter-cond-matother-cond-matother
keyword: lepton-universality-violation
keyword: supersymmetry
keyword: violation-de-luniversalite-leptonique
keyword: theses
landing page: https://theses.hal.science/tel-00922999
description: In this doctoral thesis, we study both low- and high-energy observables related to massive neutrinos. Neutrino oscillations have provided indisputable evidence in favour of non-zero neutrino masses and mixings. However, the original formulation of the Standard Model cannot account for these observations, which calls for the introduction of new Physics. Among many possibilities, we focus here on the inverse seesaw, a neutrino mass generation mechanism in which the Standard Model is extended with fermionic gauge singlets. This model offers an attractive alternative to the usual seesaw realisations since it can potentially have natural Yukawa couplings (O(1)) while keeping the new Physics scale at energies within reach of the LHC. Among the many possible effects, this scenario can lead to deviations from lepton flavour universality. We have investigated these signatures and found that the ratios R_K and R_π provide new, additional constraints on the inverse seesaw. We have also considered the embedding of the inverse seesaw in supersymmetric models. This leads to increased rates for various lepton flavour violating processes, due to enhanced contributions from penguin diagrams mediated by the Higgs and Z bosons. Finally, we also found that the new invisible decay channels associated with the sterile neutrinos present in the supersymmetric inverse seesaw could significantly weaken the constraints on the mass and couplings of a light CP-odd Higgs boson.
identifier: NNT: 2013PA112118
issued: 2026-05-07T16:25:08.019874
language: en
modified: 2026-05-07T16:25:08.019879

Effects of fermionic singlet neutrinos on high- and low-energy observables
type: Distribution
access URL: https://theses.hal.science/tel-00922999
format: HTML
issued: 2026-05-07T16:25:08.028854
modified: 2026-05-07T16:25:08.005066

test_moissonnage_selune
type: Agent