Towards a superformula for neutrinoless double beta decay

A general Lorentz-invariant parameterization for the long-range part of the 0 nu beta beta decay rate is derived. Combined with the short range part t his general parameterization in terms of effective B - L violating coupling s will allow it to extract the 0 nu beta beta limits on arbitrary lepton nu mber violating theories. Several new nuclear matrix elements appear in the general formalism compared to the standard neutrino mass mechanism. Some of these new matrix elements have never been considered before and are calcul ated within pn-QRPA. Using these, limits on lepton number violating paramet ers are derived from experimental data on Ge-76. (C) 1999 Elsevier Science B.V. All rights reserved.