Radiative inverse seesaw model with hidden $U(1)$ gauge symmetry enhancing lepton $g-2$

TL;DR

The paper addresses how to generate tiny neutrino masses at a low scale while accounting for a possible muon $g-2$ anomaly. It develops a hidden $U(1)_H$-based model in which an inverse seesaw is induced at one loop, with vector-like leptons and charged scalars driving neutrino masses via $m_\nu \simeq (m_D M_N^{-1})\,\delta m_{33}\,(m_D M_N^{-1})^T$ and generating correlated LFV and EDM signals. The authors perform a numerical analysis enforcing neutrino oscillation data and non-unitarity bounds, finding that the new physics scale $\mu_{NP}$ can be as low as $\mathcal{O}(1)$ TeV for IO or $\mathcal{O}(100)$ TeV for NO to yield $\Delta a_\mu$ in the interesting range, while LFV and EDM constraints shape the allowed Yukawa textures. The framework predicts testable collider signatures from charged leptons and scalars and offers prospects for upcoming LFV and precision $g-2$ measurements to probe the parameter space.

Abstract

We propose a new inverse seesaw model based on hidden local $U(1)$ symmetry framework where inverse seesaw mechanism is induced at one loop level. A Majorana mass term of singlet fermion is forbidden by the $U(1)$ symmetry and it is generated at one-loop level by introducing relevant particle contents to get loop diagram, inducing inverse seesaw mechanism. The same particle contents also contribute to lepton magnetic(electric) dipole moment and lepton flavor violating decays without chiral suppression. We can then obtain sizable muon anomalous magnetic dipole moment that accommodate with deviation from the standard model prediction. The constraints from lepton flavor violating decays and electron magnetic(electric) dipole moment are also discussed to explore testability of the model.

Figures (8)

• Figure 1: One-loop diagram that generates Majorana mass term of $N_{L(R)}$.
• Figure 2: One-loop diagram contributing lepton $g-2$, EDM and LFV decay amplitude.
• Figure 3: Diagrams for modifying interactions between $Z$ and SM charged leptons where dashed line indicate charged scalar bosons.
• Figure 4: $\Delta a_\mu$ and $BR(\ell \to \ell' \gamma)$ for allowed parameter sets where horizontal dot-dashed line shows current constraint from $BR(\mu \to e \gamma)$, and region between vertical solid, dashed and dotted lines indicate $1\sigma$, $2\sigma$ and $3\sigma$ range of $\Delta a_\mu^{\rm data-driven}$. In addition, vertical orange-solid and orange-dashed lines indicate $1\sigma$ and $2\sigma$ upper bound of $\Delta a_\mu^{\rm WP25}$. The left(right) plot corresponds to NO(IO) case.
• Figure 5: $\mu_{NP}$ and $\Delta a_\mu$ for allowed parameter sets where region between horizontal solid, dashed and dotted lines indicate $1\sigma$, $2\sigma$ and $3\sigma$ range of $\Delta a_\mu^{\rm data-driven}$. In addition, horizontal orange-solid and orange-dashed lines indicate $1\sigma$ and $2\sigma$ upper bound of $\Delta a_\mu^{\rm WP25}$. The left(right) plot corresponds to NO(IO) case.