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Abstract

We discuss a mechanism of neutrinoless double beta decay, where
neutrinos of different flavors come into play. This is realized by
effective flavor-violating scalar interactions. As one consequence, we
find that within the normal mass ordering the neutrino effective mass
may no longer vanish due to contributions from other flavors. We
evaluate the necessary nuclear matrix elements, consider the
interference between the standard diagram and the new scalar one, and
analyze a UV-complete model that realizes the scalar interaction. Tests
of the complete model are possible at colliders and future neutrino
experiments. Our scenario represents an alternative mechanism for
neutrinoless double beta decay, where nevertheless lepton number
violation resides only in Majorana mass terms of light neutrinos.