Description of the ov beta beta decay of48Ca,76Ge,100Mo,128,130Te

A large Hilbert space is used for the calculation of the nuclear matrix elements governing the light neutrino mass mediated mode of neutrinoless double beta decay (0νββ-decay) of 76 Ge, 100 M o, 116 Cd, 128 T e and 136 Xe within the proton-neutron quasiparticle random phase approximation (pn-QRPA) and the renormalized QRPA with proton-neutron pairing (full-RQRPA) methods.We have found that the nuclear matrix elements obtained with the standard pn-QRPA for several nuclear transitions are extremely sensitive to the renormalization of the particle-particle component of the residual interaction of the nuclear hamiltonian. Therefore the standard pn-QRPA does not guarantee the necessary accuracy to allow us to extract a reliable limit on the * Supported by the "Deutsche The full-RQRPA, which takes into account proton-neutron pairing and considers the Pauli principle in an approximate way, offers a stable solution in the physically acceptable region of the particle-particle strength. In this way more accurate values on the effective neutrino mass have been deduced from the experimental lower limits of the half-lifes of neutrinoless double beta decay.

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“…The short-range correlations between the two interacting nucleons are now taken into account by a correlation function [5,10].…”

Section: νmentioning

confidence: 99%

A large Hilbert space QRPA and RQRPA calculation of neutrinoless double beta decay

et al. 1997

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“…The calculation of the 0νββ-decay matrix elements is based on some approximation schemes, from which the Quasiparticle Random Phase Approximation (QRPA) is the most prominent one [5]- [8], despite an uncertainty in the calculation of the nuclear matrix element, which is related to its sensitivity on the renormalization of the particle-particle component of the residual interaction. Thus in the framework of proton-neutron QRPA (pn-QRPA) using the zero range delta-force Engel et al [6] have found a strong suppression of the 0νββ-decay matrix elements by introducing short-range correlations, whereas Tomoda et al [5] and Muto et al [7] by using a more realistic effective NN interaction arrived at the opposite conclusion.…”

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“…Here, R = r 0 A 1/3 is the nuclear radius (r 0 = 1.1 fm) and the parameter Λ of the dipole shape nucleon form factor is chosen to be 0.85 GeV [8,10]. In the full-RQRPA for the matrix elements of the one-body transition densities we obtain…”

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Non-collapsing renormalized QRPA with proton-neutron pairing for neutrinoless double beta decay

et al. 1997

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Using the renormalized quasiparticle random phase approximation (RQRPA), we calculate the light neutrino mass mediated mode of neutrinoless double beta decay (0νββ-decay) of 76 Ge, 100 M o, 128 T e and 130 T e. Our results indicate that the simple quasiboson approximation is not good enough to study the 0νββ-decay, because its solutions collapse for physical values of g pp . We find that extension of the Hilbert space and inclusion of the Pauli Principle in the QRPA with proton-neutron pairing, allows us to extend our calculations beyond the point of collapse, for physical values of the nuclear force strength.

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“…In recent years, following the work of Vogel and Zirnbauer [1], the proton-neutron (pn) quasiparticle random phase approximation (QRPA) has turned out to be the most popular model for calculating the nuclear wave functions involved in the ββ-transitions [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]. The QRPA calculations have shown that the ground state correlations (GSC), induced by the residual pn interaction in the particle-particle (PP) channel, play an essential role in quenching the ββ 2ν decay probabilities.…”

Section: Introductionmentioning

confidence: 99%

Double-beta decay in pn-QRPA model with isospin and SU(4) symmetry constraints

Krmpotić

Sharma

1994

Nuclear Physics A

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The transition matrix elements for the 0 + → 0 + double beta decays are calculated for 48 Ca, 76 Ge, 82 Se, 100 Mo, 128 T e and 130 T e nuclei, using a δ-interaction. As a guide, to fix the particle-particle interaction strengths, we exploit the fact that the missing symmetries of the mean field approximation are restored in the random phase approximation by the residual interaction. Thus, the T = 1, S = 0 and T = 0, S = 1 coupling strengths have been estimated by invoking the partial restoration of the isospin and Wigner SU (4) symmetries, respectively. When this recipe is strictly applied, the calculation is consistent with the experimental limit for the 2ν lifetime of 48 Ca and it also correctly reproduces the 2ν lifetime of 82 Se. In this way, however, the two-neutrino matrix elements for the remaining nuclei are either underestimated (for 76 Ge and 100 Mo) or overestimated (for 128 T e and 130 T e) approximately by a factor of 3. With a comparatively small variation (< 10%) of the spin-triplet parameter, near the value suggested by the SU(4) symmetry, it is possible to reproduce the measured T 2ν 1/2 in all the cases. The upper limit for the effective neutrino mass, as obtained from the theoretical estimates of 0ν matrix elements, is < m ν > ∼ = 1 eV. The dependence of the nuclear matrix elements on the size of the configuration space has been also analyzed. † Fellow of the CONICET from Argentina * Financial support from CNPq, Brazil is acknowledged

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Description of the ov beta beta decay of⁴⁸Ca,⁷⁶Ge,¹⁰⁰Mo,^128,130Te

Cited by 40 publications

References 35 publications

A large Hilbert space QRPA and RQRPA calculation of neutrinoless double beta decay

A large Hilbert space QRPA and RQRPA calculation of neutrinoless double beta decay

Non-collapsing renormalized QRPA with proton-neutron pairing for neutrinoless double beta decay

Double-beta decay in pn-QRPA model with isospin and SU(4) symmetry constraints

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