Abstract. In this contribution we present a study of a direct and sequential two-nucleon transfer within the microscopic Interacting Boson Model (IBM-2) and Interacting BosonFermion Model (IBFM), respectively. We present our preliminary results for heavy-ion doublecharge-exchange 40 Ca( 18 O, 18 Ne) 40 ArG.S. differential cross section too.
IntroductionNeutrinoless double beta decay (0νββ) is one of the most important process that has not been observed yet, and it represents a probe of physics beyond the Standard Model. One open problem is that the 0νββ decay depends on nuclear matrix elements (NMEs) that when evaluated using different nuclear structure models can differ also by about a factor of 2-3 [1]. A better understanding of the nuclear structure will help to improve the model calculation of nuclear reactions and decay processes, such as single beta decay, double beta decay (2νββ), and 0νββ. The knowledge of the internal degrees of freedom is crucial to understand nuclear structure. In order to calculate the competing two-nucleon processes to heavy-ion double charge exchange (DCE), recently we developed the formalism using microscopic IBM-2 for the NUMEN collaboration [2,3,4], and this formalism has been already applied with success to 64 Ni ( 18 O, 16 O) 66 Ni two-neutron transfer as reported here in section 2 and 3. Finally, since our goal is to describe the DCE differential cross section using IBMs for the nuclear part, trying to extract information on NMEs of nuclei involved also in 0νββ, we present here in the last section very preliminary results regarding DCE 40 Ca( 18 O, 18 Ne) 40 Ar G.S. differential cross section.