Testable two-loop radiative neutrino mass model based on an LLQd c Qd c effective operator

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 ϵ ik ϵ 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 μ → eγ, μ → eee, and μN → 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.