We discuss the contributions of lepton-number-violating sources to
neutrinoless double beta decay (0νββ). Assuming that these sources
arise at scales well above the electroweak scale, they can be described within
an effective field theory. Here, we outline the steps required to express the
0νββ half-life in terms of the effective interactions, focusing on
the dimension-five operator that induces a Majorana mass for the neutrinos.
This process involves the evolution of the operators down to scales of a few
GeV where they can be matched onto Chiral Perturbation Theory. The resulting
Chiral Lagrangian can then used be to derive the lepton-number violating
potential, which, in combination with many-body methods, gives the
0νββ half-life. We will show that consistent renormalization
requires the inclusion of a new contact interaction at leading order in this
potential. We also briefly comment on the constraints that can be set on the
operators appearing beyond dimension five.Comment: Corrected referenc