Testable two-loop radiative neutrino mass model based on an $LLQd^cQd^c$ effective operator

TL;DR

This paper introduces a two-loop radiative neutrino mass model based on an effective operator, fitting neutrino data while satisfying experimental bounds, and proposes ways to test it through flavor violation and collider experiments.

Contribution

The paper presents a novel two-loop radiative neutrino mass model with specific scalar leptoquarks and a color-octet fermion, including a computational package for relevant integrals.

Findings

Model fits neutrino oscillation data

Model complies with flavor-violation and collider bounds

Provides computational tools for Passarino-Veltman integrals

Abstract

A new two-loop radiative Majorana neutrino mass model is constructed from the gauge-invariant effective operator $L^i L^j Q^k d^c Q^l d^c \epsilon_{ik} \epsilon_{jl}$ that violates lepton number conservation by two units. The ultraviolet completion features two scalar leptoquark flavors and a color-octet Majorana fermion. We show that there exists a region of parameter space where the neutrino oscillation data can be fitted while simultaneously meeting flavor-violation and collider bounds. The model is testable through lepton flavor-violating processes such as ${\mu} \to e{\gamma}$, $\mu \to eee$, and $\mu N \to eN$ conversion, as well as collider searches for the scalar leptoquarks and color-octet fermion. We computed and compiled a list of necessary Passarino-Veltman integrals up to boxes in the approximation of vanishing external momenta and made them available as a Mathematica package, denoted as ANT.