  The article describes the main achievements of the NUMEN project together
with an updated and detailed overview of the related R&D activities and
theoretical developments. NUMEN proposes an innovative technique to access the
nuclear matrix elements entering the expression of the lifetime of the double
beta decay by cross section measurements of heavy-ion induced Double Charge
Exchange (DCE) reactions. Despite the two processes, namely neutrinoless double
beta decay and DCE reactions, are triggered by the weak and strong interaction
respectively, important analogies are suggested. The basic point is the
coincidence of the initial and final state many-body wave-functions in the two
types of processes and the formal similarity of the transition operators. First
experimental results obtained at the INFN-LNS laboratory for the
40Ca(18O,18Ne)40Ar reaction at 270 MeV, give encouraging indication on the
capability of the proposed technique to access relevant quantitative
information. The two major aspects for this project are the K800
Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the
acceleration of the required high resolution and low emittance heavy ion beams
and the latter is the large acceptance magnetic spectrometer for the detection
of the ejectiles. The use of the high-order trajectory reconstruction
technique, implemented in MAGNEX, allows to reach the experimental resolution
and sensitivity required for the accurate measurement of the DCE cross sections
at forward angles. However, the tiny values of such cross sections and the
resolution requirements demand beam intensities much larger than manageable
with the present facility. The on-going upgrade of the INFN-LNS facilities in
this perspective is part of the NUMEN project and will be discussed in the
article.
