ISSN:
1434-601X
Keywords:
21.60−n
;
23.40−s
;
23.40.Hc
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Nuclear matrix elements of the two-neutrino and neutrinolessββ decays of48Ca(0 g.s. + )→48Ti(0 g.s. + ) are calculated by shell model and QRPA. The two-neutrino matrix elementM GT 2v is rather reliably evaluated in the QRPA approach by a careful fit of the particle-particle interaction strength in the 1+ channel, which governs the spinisospin ground-state correlations. The shell-model value ofM GT 2v depends not only on the 1+ interaction but largely on the pairing and quadrupole interactions. Concerning the neutrinoless-mode nuclear matrix elements, the shell model gives generally smaller values than the QRPA. A detailed analysis indicates that the discrepancies originate mainly from the truncation of shell-model configurations (fp-space). The QRPA calculation in a larger model space well takes into account transitions from/to single-particle orbits far from the Fermi surface, and those transitions give rise to sizable contributions because of large momentum transfers due to the exchange of a virtual neutrino.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01288427
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