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Madey, R.; Flanders, B. S.; Anderson, B.D.; Baldwin, A. R.; Watson, J. W.; Austin, Sam M.; Foster, C.C.; Klapdor, H. V.; Grotz, K.

doi:10.1103/physrevc.40.540

Cited by 78 publications

(71 citation statements)

References 22 publications

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“…The thick solid line in Fig. 7 corresponds to data obtained from charge exchange 76 Ge(p, n) 76 As reaction at 134.4 MeV [50], which were folded with 1 MeV width Gaussians as it has been done for the theoretical results. We see that the presented calculations are in a very good agreement with data for the position of Gamow-Teller resonance.…”

Section: νmentioning

confidence: 99%

Two-neutrino double beta decay of 76Ge within deformed QRPA

2004

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The effect of deformation on the two-neutrino double decay (2νββ-decay) for ground state transition 76 Ge → 76 Se is studied in the framework of the deformed QRPA with separable Gamow-Teller residual interaction. A new suppression mechanism of the 2νββ-decay matrix element based on the difference in deformations of the initial and final nuclei is included. An advantage of this suppression mechanism in comparison with that associated with ground state correlations is that it allows a simultaneous description of the single β and the 2νββ-decay. By performing a detail calculation of the 2νββ-decay of 76 Ge, it is found that the states of intermediate nucleus lying in the region of the Gamow-Teller resonance contribute significantly to the matrix element of this process.

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Section: νmentioning

confidence: 99%

Two-neutrino double beta decay of 76Ge within deformed QRPA

2004

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“…The experimental Gamow-Teller resonance energies are from Refs. [28][29][30][31][32], the spin-dipole resonance energies from Refs. [33,34], and the half-lifes from Ref.…”

Section: Skyrme Functional and Computational Methodsmentioning

confidence: 99%

Global description ofβ−decay in even-even nuclei with the axially-deformed Skyrme finite-amplitude method

2016

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We use the finite amplitude method for computing charge-changing Skyrme-QRPA transition strengths in axially-deformed nuclei together with a modern Skyrme energy-density functional to fit several previously unconstrained parameters in the charge-changing time-odd part of the functional. With the modified functional we then calculate rates of beta-minus decay for all medium-mass and heavy even-even nuclei between the valley of stability and the neutron drip line. We fit the Skyrme parameters to a limited set of beta-decay rates, a set of Gamow-Teller resonance energies, and a set of spin-dipole resonance energies, in both spherical and deformed nuclei. Comparison to available experimental beta-decay rates shows agreement at roughly the same level as in other global QRPA calculations. We estimate the uncertainty in our rates all the way to the neutron drip line through a construction that extrapolates the errors of known beta-decay rates in nuclei with intermediate Q values to less stable isotopes with higher Q values.

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“…6 are obtained in a phenomenological way using the experimental GT strengths of the transitions 76 Ge → 76 As (GT − ) [19] and 76 Se → 76 As (GT + ) [20], as explained in previous experimental or theoretical works [9,20]. An experimental range for the final value of the matrix element is also shown in the plot, obtained from the experimental double-β decay half-life [21] with two possible values of the axial-to-vector ratio g A = 1.25 and g A = 1.00 (quenched value).…”

mentioning

confidence: 99%

Theoretical mean-field and experimental occupation probabilities in the double-βdecay systemGe76to
Moreno
¹
,
Guerra
²
,
Sarriguren
³

et al. 2010
Phys. Rev. C
14
1
6
0
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Usual Woods-Saxon single-particle levels with BCS pairing are not able to reproduce the experimental occupation probabilities of the proton and neutron levels 1p 3/2 , 1p 1/2 , 0f 5/2 , and 0g 9/2 in the double-β decay system 76 Ge to 76 Se. Shifting down the 0g 9/2 level by hand can explain the data, but it is not satisfactory. Here it is shown that a self-consistent Hartree-Fock + BCS approach with experimental deformations for 76 Among double-β decay-with-two-neutrino processes, the best-studied case is that of 76 Ge going to 76 Se. Within a spherically symmetric description of these nuclei, the relevant proton and neutron single-particle levels involved in the double-β decay process are in the valence shells 1p 3/2 , 1p 1/2 , 0f 5/2 , and 0g 9/2 . Their occupation probabilities were measured recently by Schiffer et al.[1] (for neutrons) and by Kay et al. [2] (for protons). These data are not reproduced by previous mean-field calculations using Woods-Saxon potential and pairing within BCS approximation. By increasing the binding energy of the 0g 9/2 level, the agreement is better, because its occupation probability increases and eventually reaches the experimental one. This energy shifting has been performed by hand in previous works [3][4][5] to obtain the experimental occupation probabilities, and the resulting ground-state structure has been used to compute neutrinoless double-β matrix elements. Shell-model calculations [6] have also been carried out with occupation probabilities in good agreement with experimental ones, but the single-particle energies used are not available in the literature.In this work we use a deformed Skyrme Hartree-Fock (HF) mean-field with pairing correlations within BCS approximation. At each HF iteration the BCS equations are solved to get new single-particle wave functions i , energies e i , and occupation probabilities v 2 i until convergence is achieved. After convergence, the proton-neutron quasiparticle randomphase approximation (pnQRPA) equations are solved on each deformed ground-state basis for 76 Ge and 76 Se to get their Gamow-Teller (GT) strength distributions and to compute the two-neutrino double-β decay matrix element. The formalism is similar to that used in previous works [7][8][9] with an important difference. In this work we allow the Skyrme force parameters to vary and search for a parametrization that provides better agreement with the experimental occupations of the previously mentioned valence shells in 76 Ge and 76 Se, as well as in their neighbors. We focus on the effect of the spin-orbit strength, W 0 , which we find to be of primary importance for the desired description of proton and neutron valence-shell occupations.Experimental data and HF + BCS calculations suggest prolate deformations for the 76 Ge and 76 Se ground states. The most precise data on the quadrupole moments of these nuclei come from Coulomb excitation reorientation measurements [10], which, together with experimental charge radii [11], give a deformation parameter β = 0.10 for 76 Ge ...

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Low-lying structures in the Gamow-Teller strength functions for the double-beta-decaying nucleiGe76,<

Cited by 78 publications

References 22 publications

Two-neutrino double beta decay of 76Ge within deformed QRPA

Two-neutrino double beta decay of 76Ge within deformed QRPA

Global description ofβ−decay in even-even nuclei with the axially-deformed Skyrme finite-amplitude method

Theoretical mean-field and experimental occupation probabilities in the double-βdecay systemGe76to
Moreno
¹
,
Guerra
²
,
Sarriguren
³

et al. 2010
Phys. Rev. C
14
1
6
0
View full text Add to dashboard Cite

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Low-lying structures in the Gamow-Teller strength functions for the double-beta-decaying nucleiGe76,<

Cited by 78 publications

References 22 publications

Two-neutrino double beta decay of 76Ge within deformed QRPA

Two-neutrino double beta decay of 76Ge within deformed QRPA

Global description ofβ−decay in even-even nuclei with the axially-deformed Skyrme finite-amplitude method

Theoretical mean-field and experimental occupation probabilities in the double-βdecay systemGe76toMoreno1, Guerra2, Sarriguren3 et al. 2010Phys. Rev. C14160View full textAdd to dashboardCite

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About

Theoretical mean-field and experimental occupation probabilities in the double-βdecay systemGe76to
Moreno
¹
,
Guerra
²
,
Sarriguren
³

et al. 2010
Phys. Rev. C
14
1
6
0
View full text Add to dashboard Cite