# The Neutrino Option

## TL;DR

The Neutrino Option proposes that neutrino masses and the Higgs mass originate simultaneously within a type-I seesaw model, offering a novel perspective on the hierarchy problem and linking neutrino physics with electroweak symmetry breaking.

## Contribution

This paper refines the parameter space where the Neutrino Option is viable, integrating experimental constraints and exploring potential signatures and cosmological implications.

## Key findings

- Heavy Majorana neutrinos with masses 0.5-10 PeV can accommodate experimental constraints.
- The scenario can naturally generate the Higgs mass and neutrino masses simultaneously.
- Conformal UV completions and gravitational wave detection are potential tests of the model.

## Abstract

The Neutrino Option is a scenario where the Higgs mass is generated at the same time as neutrino masses in the type-I seesaw model. This framework provides a dynamical origin for the scalar potential of the Standard Model and suggests a new approach to the hierarchy problem. Here we review the preliminary analysis of Ref. [1], that showed the viability of this scenario, as well as the improved study of Ref. [2], that led to a better identification of the region of the parameter space where the Neutrino Option can be realized. We find that experimental constraints from both Higgs and neutrino physics can be accommodated introducing 2 heavy Majorana neutrinos with mass $M_1\simeq M_2\sim 0.5 - 10$ PeV and Yukawa couplings to the lepton doublet of order $ 10^{-4}-10^{-2}$, assuming that at the scale $M$ the classical Higgs potential is approximately conformal, with a quartic Higgs coupling $\lambda_0\sim 0.01-0.05$. Specifying the light neutrino mass ordering, the ratio $M_2/M_1$ or a given value of the top quark mass identifies narrower ranges for all the parameters. Although no further signature of the Neutrino Option is generally predicted at the currently accessible energy scales, conformal UV completions have been proposed, that could be tested e.g. via detection of gravitational waves. Leptogenesis can also be successfully realized in this scenario, that intriguingly ties together the breaking of the conformal and electroweak symmetries with the violation of lepton number.