Probing the quenching of gA by single and double beta decays

Ground-state-to-ground-state two-neutrino double beta (2νββ) decays and single beta (EC and β−) decays are studied for the A=100 (100Mo100Tc100Ru), A=116 (116Cd116In116Sn) and A=128 (128Te128I128Xe) nuclear systems by using the proton–neutron quasiparticle random-phase approximation exploiting realistic effective interactions in very large single-particle bases. The aim of this exercise is to see if both the single-beta and double-beta decay observables related to the ground states of the initial, intermediate and final nuclei participant in the decays can be described simultaneously by changing the value of the axial-vector coupling constant gA. In spite of the very different responses to single and 2νββ decays of the considered nuclear systems, the obtained results point consistently to a quenched effective value of gA that is (slightly) different for the single and 2νββ decays.Fil: Suhonen, Jouni. Universidad de Jyvaskyla; FinlandiaFil: Civitarese, Enrique Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Double beta decay to the excited states: experimental review

A brief review on double beta decay to excited states of daughter nuclei is given. The ECEC(ov) transision to the excited states are discussed in association with a possible enhancement of the decay rate by several orders of magnitude.Comment: 5 pages; talk at MEDEX'07 ("Matrix Elements for the Double-beta-decay Experiments"; Prague, June 11-14, 2007

Nuclear matrix elements for double beta decay in the QRPA approach: a critical review

The calculation of nuclear matrix elements (NME) for double beta decay transitions (DBD) relies upon several approximations. The purpose of this note is to review some of these approximations, and their impact upon the NME. We shall present our results, which have been obtained in the framework of the proton-neutron quasiparticle random phase approximation (pnQRPA), and we shall focus on short range correlations, pairing, and symmetry effects.Facultad de Ciencias Exacta

Probing the quenching of gA by single and double beta decays

Ground-state-to-ground-state two-neutrino double beta (2νββ) decays and single beta (EC and β−) decays are studied for the A=100 (100Mo100Tc100Ru), A=116 (116Cd116In116Sn) and A=128 (128Te128I128Xe) nuclear systems by using the proton–neutron quasiparticle random-phase approximation exploiting realistic effective interactions in very large single-particle bases. The aim of this exercise is to see if both the single-beta and double-beta decay observables related to the ground states of the initial, intermediate and final nuclei participant in the decays can be described simultaneously by changing the value of the axial-vector coupling constant gA. In spite of the very different responses to single and 2νββ decays of the considered nuclear systems, the obtained results point consistently to a quenched effective value of gA that is (slightly) different for the single and 2νββ decays.Facultad de Ciencias Exacta

Nuclear matrix elements for double beta decay in the QRPA approach: a critical review

The calculation of nuclear matrix elements (NME) for double beta decay transitions (DBD) relies upon several approximations. The purpose of this note is to review some of these approximations, and their impact upon the NME. We shall present our results, which have been obtained in the framework of the proton-neutron quasiparticle random phase approximation (pnQRPA), and we shall focus on short range correlations, pairing, and symmetry effects.Facultad de Ciencias Exacta