Systematic study of beta and double beta decay to excited final states
Abstract
A systematic study of the twoneutrino double beta (2νββ) decay to the final ground state and excited states is performed within an extension of the quasiparticle randomphase approximation (QRPA) model. In this extension, the multiple commutator model (MCM), a simultaneous treatment of the doubleodd and doubleeven nuclei is possible by assuming their states to have the structure of one or two QRPA phonons. The MCM calculation is done for nine 2 νβ^{}β^{} decays and six 2νECEC decays, and systematics of the relevant matrix elements and halflives have been created. The study of the 2νββdecay rates is complemented with the MCM study of the singlebetadecay properties of the relevant nuclei within the doublebeta isobaric chains. The WoodsSaxon singleparticle energies have been corrected near the Fermi surface by comparing the BCS quasiparticle energies with spectroscopic data of oddmass nuclei. Pairing gaps, energy systematics of the GamowTeller states and the available betadecay data have been used to obtain effective, modelspace adapted, twobody matrix elements starting from the Gmatrix elements of the Bonn onebosonexchange potential. This enables a parameterfree calculation of the double GamowTeller matrix elements and theoretical prediction of doublebeta halflives.
 Publication:

Nuclear Physics A
 Pub Date:
 February 1996
 DOI:
 10.1016/03759474(96)000875
 Bibcode:
 1996NuPhA.602..133A