Isospin dependence of electromagnetic transition strengths among an isobaric triplet

Summary, in English

Electric quadrupole matrix elements, M_p, for the J^π=2⁺→0⁺, ΔT=0, T=1 transitions across the A=46 isobaric multiplet ⁴⁶Cr-⁴⁶V-⁴⁶Ti have been measured at GSI with the FRS-LYCCA-AGATA setup. This allows direct insight into the isospin purity of the states of interest by testing the linearity of M_p with respect to T_z. Pairs of nuclei in the T=1 triplet were studied using identical reaction mechanisms in order to control systematic errors. The M_p values were obtained with two different methodologies: (i) a relativistic Coulomb excitation experiment was performed for ⁴⁶Cr and ⁴⁶Ti; (ii) a “stretched target” technique was adopted here, for the first time, for lifetime measurements in ⁴⁶V and ⁴⁶Ti. A constant value of M_p across the triplet has been observed. Shell-model calculations performed within the fp shell fail to reproduce this unexpected trend, pointing towards the need of a wider valence space. This result is confirmed by the good agreement with experimental data achieved with an interaction which allows excitations from the underlying sd shell. A test of the linearity rule for all published data on complete T=1 isospin triplets is presented.

• Author: A. Boso; S. A. Milne; M. A. Bentley; F. Recchia; S. M. Lenzi; D. Rudolph; M. Labiche; X. Pereira-Lopez; S. Afara; F. Ameil; T. Arici; S. Aydin; M. Axiotis; D. Barrientos; G. Benzoni; B. Birkenbach; A. J. Boston; H. C. Boston; P. Boutachkov; A. Bracco; A. M. Bruce; B. Bruyneel; B. Cederwall; E. Clement; M. L. Cortes; D. M. Cullen; P. Désesquelles; Zs Dombràdi; C. Domingo-Pardo; J. Eberth; C. Fahlander; M. Gelain; V. González; P. R. John; J. Gerl; P. Golubev; M. Górska; A. Gottardo; T. Grahn; L. Grassi; T. Habermann; L. J. Harkness-Brennan; T. W. Henry; H. Hess; I. Kojouharov; W. Korten; N. Lalović; M. Lettmann; C. Lizarazo; C. Louchart-Henning; R. Menegazzo; D. Mengoni; E. Merchan; C. Michelagnoli; B. Million; V. Modamio; Th. Moeller; D. R. Napoli; J. Nyberg; B. S. Nara Singh; H. Pai; N. Pietralla; S. Pietri; Zs Podolyak; R. M. Perez Vidal; A. Pullia; D. Ralet; G. Rainovski; M. Reese; P. Reiter; M. D. Salsac; E. Sanchis; L. G. Sarmiento; H. Schaffner; L. M. Scruton; P.P. Singh; C. Stahl; S. Uthayakumaar; J. J. Valiente-Dobón; O. Wieland
• Department/s: Nuclear physics
• Publishing year: 2019-10-10
• Language: English
• Publication/Series: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
• Volume: 797
• Full text: - 446 kB; Download statistics
• Links: http://dx.doi.org/10.1016/j.physletb.2019.134835
• Document type: Journal article
• Publisher: Elsevier
• Topic: Subatomic Physics
• Status: Published
• Project: Nuclear Structure at the Limits: Isotope-selective Spectroscopy; FAIR-NUSTAR: HISPEC-DESPEC experiment & Super-FRS contributions
• ISBN/ISSN/Other: ISSN: 0370-2693