Evidence for rigid triaxial deformation in \(^{76}\)Ge from a model-independent analysis

• Published in: arXiv.org
• Main Authors: Ayangeakaa, A D, Janssens, R V F, Zhu, S, Little, D, Henderson, J, Wu, C Y, Hartley, D J, Albers, M, Auranen, K, Bucher, B, Carpenter, M P, Chowdhury, P, Cline, D, Crawford, H L, Fallon, P, ney, A M, Gade, A, Hayes, A B, Kondev, F G, Krishichayan, Lauritsen, T, J Li, Macchiavelli, A O, Rhodes, D, Seweryniak, D, Stolze, S M, Walters, W B, J Wu
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 07.09.2019
• Subjects: Beta decay; Deformation; Mathematical models; Parameters; Physics - Nuclear Experiment; Physics - Nuclear Theory; Quadrupoles; Variations
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1909.03270

An extensive, model-independent analysis of the nature of triaxial deformation in \(^{76}\)Ge, a candidate for neutrinoless double-beta (\(0\nu\beta\beta\)) decay, was carried out following multi-step Coulomb excitation. Shape parameters deduced on the basis of a rotational-invariant sum-rule analysis provided considerable insight into the underlying collectivity of the ground-state and \(\gamma\) bands. Both sequences were determined to be characterized by the same \(\beta\) and \(\gamma\) deformation parameter values. In addition, compelling evidence for low-spin, rigid triaxial deformation in \(^{76}\)Ge was obtained for the first time from the analysis of the statistical fluctuations of the quadrupole asymmetry deduced from the measured \(E2\) matrix elements. These newly determined shape parameters are important input and constraints for calculations aimed at providing, with suitable accuracy, the nuclear matrix elements relevant to \(0\nu\beta\beta\).