Neutrino masses from fine tuning

Abstract

We present a new approach for generating tiny neutrino masses. The Dirac neutrino mass matrix gets contributions from two new Higgs doublets with their vevs at the electroweak (EW) scale. Neutrino masses are tiny not because of tiny Yukawa couplings, or very heavy ( ∼ 10 14 GeV ) right-handed neutrinos. They are tiny because of a cancellation in the Dirac neutrino mass matrix (fine tuning). After fine tuning to make the Dirac neutrino mass matrix at the 10 − 4 GeV scale, light neutrino masses are obtained in the correct scale via the see-saw mechanism with the right-handed neutrino at the EW scale. The proposal links neutrino physics to collider physics. The Higgs search strategy is completely altered. For a wide range of Higgs masses, the Standard Model Higgs decays dominantly to ν L N R mode giving rise to the final state ν ¯ ν b ¯ b , or ν ¯ ν τ + τ − . This can be tested at the LHC, and possibly at the Tevatron.