GeV Seesaw, Accidentally Small Neutrino Masses, and Higgs Decays to Neutrinos

Abstract

If the Standard Model particle content is extended by gauge singlet fermions (right-handed neutrinos), active neutrinos generically acquire (Majorana) masses, in agreement with our current understanding of the lepton sector. If the right-handed neutrino masses are of the same order as the electroweak symmetry breaking scale, it is usually expected that these will not mediate any experimentally observable effects. Here, I explore the fact that this is not necessarily the case. If neutrino masses are "accidentally small", active-sterile mixing angles can, according to current experimental bounds, be as large as several percent. If this is the case, I argue that the dominant decay mode of light (M_H less than 130 GeV) Higgs bosons could be into an active and a sterile neutrino. The sterile neutrino decays promptly into a charge lepton and an on- or off-shell W-boson, so that the dominant Higgs boson decay mode is H to leptons + jets + missing transverse energy.

11 pages, revtex, 3 eps figures, references and constraint added, conclusions unchanged

Cited by in corpus (6)

• Lepton Number Violation and W' Chiral Couplings at the LHC
• Low-energy limits on heavy Majorana neutrino masses from the neutrinoless double-beta decay and non-unitary neutrino mixing
• Probing Neutrino Dirac Mass in Left-Right Symmetric Models at the LHC and Next Generation Colliders
• ALP-portal majorana dark matter
• Expression of Interest for Neutrinos Scattering on Glass: NuSOnG
• Type I Seesaw Mechanism, Lepton Flavour Violation and Higgs Decays