Gravitational waves from supercooled phase transitions in conformal Majoron models of neutrino mass

TL;DR

This paper investigates supercooled phase transitions in conformal Majoron models that explain neutrino masses and predicts a stochastic gravitational wave background detectable by current and future observatories, constraining model parameters.

Contribution

It introduces a comprehensive analysis of gravitational wave signals from supercooled phase transitions in conformal Majoron models, linking neutrino mass mechanisms to gravitational wave observables.

Findings

Strong supercooling can be ruled out if no SGWB is detected.

Null results at LIGO and ET constrain the seesaw scale below 10^{14} GeV.

LISA can detect SGWB signals from low-scale seesaw models.

Abstract

We study supercooled first-order phase transitions above the QCD scale in a wide class of conformal Majoron-like U(1)' models that explain the totality of active neutrino oscillation data and produce a detectable stochastic gravitational wave background (SGWB) at LIGO, LISA and ET. We place constraints on the U(1)' breaking scale and gauge coupling using current LIGO-Virgo-Kagra data. We find that strong supercooling can be ruled out in large regions of parameter space if a SGWB is not detected by these experiments. A null signal at LIGO and ET will disfavor a type-I seesaw scale above $10^{14}$ GeV, while a positive signal is a signature of heavy right-handed neutrinos. On the other hand, LISA will be sensitive to seesaw scales as low as a TeV, and could detect a SGWB even if the right-handed neutrinos are decoupled.