  Neutrinos in the Standard Model (SM) are considered to be massless which is
in contradiction with the evidence from the neutrino oscillation data. These
experiments established that at least two SM neutrinos have non-zero masses and
that individual lepton numbers are violated. This is strong evidence of new
physics beyond the SM that should be responsible for generating non zero mass
for the neutrinos. In this work, we study the collider phenomenology of an
extension of the SM where neutrinos are generated radiatively at three-loop. We
show that the production of same-sign dilepton at lepton colliders (such as
FCC-ee and ILC) can be used to probe the Majorana nature of neutrinos in this
class of models.
