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Mar del Plata, Argentina

Suhonen J.,University of Jyvaskyla | Civitarese O.,University of la Plata
Nuclear Physics A | Year: 2010

Neutrinoless double beta (0νββ) decay of the 76Ge, 82Se, 128Te, 130Te and 136Xe nuclei is discussed in terms of the associated nuclear matrix element (NME). The effects of the size of the single-particle model space and the occupancies of individual orbits on the NME are discussed by using the proton-neutron quasiparticle random-phase approximation (pnQRPA) with effective, G-matrix-derived nuclear forces. It is found that only in some cases the orbital occupancies play a decisive role for the size of the NME, whereas the inclusion of all the spin-orbit partners is essential to achieve a NME of reasonable quality. The obtained results are compared with published results of other models. © 2010 Elsevier B.V. Source


Civitarese O.,University of la Plata
Nuclear and Particle Physics Proceedings | Year: 2015

This talk will be devoted to the presentation of the ANDES underground laboratory project. We shall talk about the motivations, prospects and design of this facility, which will be the first of its type in the southern hemisphere. The physics involved, as well as other potential applications to biology, geology and material sciences, are discussed. © 2015 Elsevier B.V. Source


Suhonen J.,University of Jyvaskyla | Civitarese O.,University of la Plata
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

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. © 2013 Elsevier B.V. Source


Civitarese O.,University of la Plata | Gadella M.,University of Valladolid
Foundations of Physics | Year: 2013

The classical concept of entropy was successfully extended to quantum mechanics by the introduction of the density operator formalism. However, further extensions to quantum decaying states have been hampered by conceptual difficulties associated to the particular nature of these states. In this work we address this problem, by (i) pointing out the difficulties that appear when one tries a consistent definition for this entropy, and (ii) building up a plausible formalism for it, which is based on the use of coherent complex states in the context of a path integration. © 2013 Springer Science+Business Media New York. Source


Suhonen J.,University of Jyvaskyla | Civitarese O.,University of la Plata
Journal of Physics G: Nuclear and Particle Physics | Year: 2012

We review the recent work done by the Jyväskylä-La Plata collaboration on the calculation of nuclear matrix elements for various modes of double-beta decays. Whenever helpful, we connect our recent work to the historical background in order to highlight the progress achieved in the field of double-beta decay. At the same time, we introduce some new concepts and ideas to treat e.g. possible backgrounds in Gamow-Teller strength functions generated in (p,n) and (n,p) reactions. © 2012 IOP Publishing Ltd. Source

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