Gravitational Wave Probe of Singlet-Doublet Dark Matter Induced Radiative Neutrino Mass

TL;DR

This work presents a one-loop radiative neutrino mass model with a Z2-odd dark sector consisting of a singlet fermion $χ$, a vector-like doublet $Ψ$, and three singlet scalars $φ_i$. Mixing between $χ$ and the neutral component of $Ψ$ yields singlet–doublet Majorana dark matter, while Higgs–scalar interactions $λ_{hi}$ modify the potential to enable a strong first-order electroweak phase transition, producing gravitational waves within reach of planned detectors. The same dark-sector states participate in neutrino mass generation, contribute to the muon anomalous magnetic moment, and induce charged lepton flavor violation, providing a tightly constrained, predictive framework tested via relic density, direct detection, LFV, and GW signals. The allowed parameter space favors DM masses around 100–900 GeV and a mixing angle $\sinθ$ in the $10^{-3}$–$0.1$ range, with direct-detection bounds excluding large $\sinθ$; three benchmark points illustrate compatible neutrino masses, $g-2$, LFV, DM phenomenology, and observable GWs, underscoring the model’s testability across multiple experimental frontiers.

Abstract

We investigate an one loop radiative neutrino mass model, where the loop particles, notably a singlet fermion ($χ$), a doublet fermion ($Ψ$) and three generations of singlet scalars ($φ_i, i=\{1,2,3\}$) are assumed to be odd under an additional $\mathcal{Z}_2$-symmetry. In this setup, the singlet fermion mixes with the neutral component of the doublet to give rise singlet-doublet Majorana dark matter. The addition of $\mathcal{Z}_2$ odd scalars in the model provides rich phenomenological implications. We find that the quartic interaction terms between the SM Higgs and $φ_i$s play a significant role in modifying the scalar potential to have a first-order phase transition (FOPT) leading to observable gravitational waves (GWs) spectra. We also examine the non-trivial role played by the singlet-doublet fermion DM and the scalars in loop-induced neutrino mass, $(g-2)_μ$, and lepton flavor violation. We find that the model is predictive due to the combined constraints and can be verified at different terrestrial experiments.

Figures (14)

• Figure 1: One loop realization of Majorana neutrino mass using dark sector particles in the loop.
• Figure 2: The Feynmann diagram giving rise $(g-2)_\mu$ and charged lepton flavor violation.
• Figure 3: The allowed parameter space from the neutrino mass is shown with the gray points in the plane of $y_{1e}$ vs $\sin\theta$. The colored points are consistent with the charged lepton flavor violation constraint. The color code represents the SD mass splitting, $\Delta M$.
• Figure 4: Correct DM relic parameter space in the plane of $\Delta{M}$ vs $M_{\rm DM}$ considering $\Delta M\ll\Delta{M}^\prime$.
• Figure 5: Left: DM parameter space satisfying correct relic in the plane of $\Delta{M}-M_{\rm DM}$. Right: the same points are shown in the plane of $\Delta{M^\prime}-M_{\rm DM}$. The SD mixing angle is shown in the color code. All these points satisfy the constraints from neutrino mass, $(g-2)_\mu$ and cLFV.