Extended IDM theory with low scale seesaw mechanisms

TL;DR

This work introduces an extended inert doublet model that incorporates a global U(1)_X broken to a preserved Z_2' and a stable Z_2×Z_2' to stabilize dark matter and enable layered radiative mass generation. Dark-sector CP violation propagates to the SM through loop corrections, producing weak CP phases at one loop while keeping θ_QCD vanishing up to three loops, addressing the strong CP problem in a novel radiative framework. The model naturally explains the SM mass hierarchy (tree-level third generation, one-loop first two generations, and two-loop neutrino masses via an inverse seesaw) and yields a multi-component dark matter sector consistent with relic density and direct-detection limits; it also accommodates the CMS 95 GeV diphoton excess and predicts cLFV rates within current sensitivity. Collectively, the framework links dark-sector CP dynamics to visible-sector observables and offers multiple experimental avenues (DM searches, LFV, collider signatures) to probe the proposed mechanism.

Abstract

We have developed an extension of the inert doublet model in which the CP-phases in the weak sector are generated from one-loop level corrections mediated by dark fields, while the strong-CP phase arises at three-loop. In this framework, the tiny masses of the active neutrinos are produced through a radiative inverse seesaw mechanism at a two-loop level, the masses of the first and second families of SM-charged fermions arise from a one-loop level radiative seesaw mechanism, and the third generation of SM charged fermion masses are generated at tree level. We have demonstrated that the proposed model successfully accounts for SM fermion masses and mixings. The radiative nature of the seesaw mechanisms is attributed to preserved discrete symmetries, which are required for ensuring the stability of fermionic and scalar dark matter candidates. The preserved discrete symmetries also allow for multi-component dark matter, whose annihilation processes permits to successfully reproduce the measured amount of dark matter relic abundance for an appropriate region of parameter space, which has shown to be compatible with current dark matter direct detection limits. Besides that, we explore the model's ability to explain the $95$ GeV diphoton excess observed by the CMS collaboration, showing that it readily accommodates this anomaly. We have shown that charged lepton flavor violating decays acquire rates within the current experimental sensitivity.

Figures (21)

• Figure 1: One-loop corrections to the SM u-quark
• Figure 2: ${ \if@compatibility \mathchar"010E {} \mathchar"010E }_{CP}$ as a function over ${ \if@compatibility \mathchar"010B {} \mathchar"010B }$ value in CKM parametrisation.
• Figure 3: One-loop corrections to the SM charged lepton mass matrices.
• Figure 4: Two-loop Feynman diagram contributing to the ${ \if@compatibility \mathchar"0116 {} \mathchar"0116 }$ parameter.
• Figure 5: Two-loop corrections to the SM u-quark