The Scotogenic Model with Two Inert Doublets: Parameters Space and Electroweak Precision Tests

TL;DR

This paper investigates a scotogenic model with two inert doublets, analyzing its parameter space, dark matter candidates, and electroweak precision constraints, especially the impact of recent W mass measurements.

Contribution

It provides a comprehensive analysis of the model's parameter space considering theoretical and experimental constraints, highlighting the role of oblique parameters and recent CMS W mass results.

Findings

Sizable Yukawa couplings can naturally occur due to scalar sector interference.

Only the oblique parameter ΔT is significantly affected by charged scalar mass splittings.

60% of the viable parameter space is excluded by recent CMS W mass measurement.

Abstract

In this work, we study a scotogenic extension of the Standard Model featuring two inert scalar doublets and three singlet Majorana fermions, where neutrino masses are generated radiatively at one loop. The lightest among the Majorana fermions and neutral scalars can serve as dark matter candidates. We explore the parameter space, considering theoretical constraints (perturbativity, unitarity, vacuum stability) and experimental limits (lepton flavor violation, Higgs measurements, electroweak precision observables). Our analysis identifies regions where sizable Yukawa couplings naturally arise due to constructive interference in the scalar sector. Additionally, we estimate the oblique parameters, finding that only $\Delta T$ is sensitive to charged mass splittings, while $\Delta S$ and $\Delta U$ remain small across the viable parameter space. However, 60\% of the viable parameter space is excluded by the recent CMS measurement of the $W$ boson mass, since the shift $\Delta M_W$ depends on the oblique parameters, particularly $\Delta T$ that is sensitive to scalar mass splittings.