Neutrino Masses from Fine Tuning

TL;DR

This paper proposes a novel mechanism for tiny neutrino masses via fine tuning of the Dirac mass matrix, linking neutrino physics with collider phenomenology and altering Higgs search strategies at colliders.

Contribution

It introduces a new approach where neutrino masses arise from fine tuning of the Dirac mass matrix, avoiding the need for very heavy right-handed neutrinos.

Findings

Neutrino masses are generated through fine tuning at the electroweak scale.

Standard Model Higgs decays predominantly to neutrino-related final states in this model.

Potential collider signatures include Higgs decays to neutrino and right-handed neutrino pairs.

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 ($\sim 10^{14}\textrm{GeV}$) right handed neutrinos. They are tiny because of a cancelation 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 $\nu_L N_R$ mode giving rise to the final state $\bar{\nu} \nu \bar{b} b$, or $\bar{\nu} \nu \tau^+\tau^-$. This can be tested at the LHC, and possibly at the Tevatron.