0νββ and 2νββ nuclear matrix elements in the interacting boson model with isospin restoration

Abstract

We introduce a method for isospin restoration in the calculation of nuclear matrix elements (NMEs) for 0νββ and 2νββ decay within the framework of the microscopic interacting boson model (IBM-2). With this method, we calculate the NMEs for all processes of interest in 0νβ−β− and 2νβ−β− and in 0νβ+β+, 0νECβ+, R0νECEC, 2νβ+β+, 2νECβ+, and 2νECEC. With this method, the Fermi matrix elements for 2νββ vanish, and those for 0νββ are considerably reduced.