Small Neutrino Masses from Supersymmetry Breaking
Nima Arkani-Hamed, Lawrence Hall, Hitoshi Murayama, David Smith, Neal Weiner
TL;DR
The paper addresses why neutrinos are so light and proposes that their masses arise from suppression by supersymmetry breaking rather than the conventional see-saw. It develops a low-energy effective theory with L, N, H_u, and X, showing that Dirac or Majorana light neutrinos can emerge depending on symmetry assignments, with mν scaling as $m_ν \\sim {v^{2}}/{M_{Pl}}$ in the Dirac and see-saw-like scenarios. A central novelty is the coupling of right-handed sneutrinos through an A-term to the Higgs, producing a rich sneutrino mass spectrum and a potential light sneutrino dark matter candidate, along with modified Higgs decays and collider signatures. The work further explores how flavor spurions can yield viable neutrino mass textures and large mixings, with implications for dark matter detection experiments and hadron-collider phenomenology.
Abstract
An alternative to the conventional see-saw mechanism is proposed to explain the origin of small neutrino masses in supersymmetric theories. The masses and couplings of the right-handed neutrino field are suppressed by supersymmetry breaking, in a way similar to the suppression of the Higgs doublet mass, $μ$. New mechanisms for light Majorana, Dirac and sterile neutrinos arise, depending on the degree of suppression. Superpartner phenomenology is greatly altered by the presence of weak scale right-handed sneutrinos, which may have a coupling to a Higgs boson and a left-handed sneutrino. The sneutrino spectrum and couplings are quite unlike the conventional case - the lightest sneutrino can be the dark matter and predictions are given for event rates at upcoming halo dark matter direct detection experiments. Higgs decays and search strategies are changed. Copious Higgs production at hadron colliders can result from cascade decays of squarks and gluinos.