First determination of the isospin mixing in the 8Be 2+ doublet via 8B beta decay
Artikel i vetenskaplig tidskrift, 2026
We report on the first experimental determination of the Fermi β strength in the β -decay of 8B, enabled by significant improvements in production yields at ISOLDE/CERN. This allows the direct observation of isospin mixing in the 16.6 and 16.9 MeV 2+ doublet in 8Be. Specifically, the 16.9 MeV state is resolved in β -decay for the first time with sufficient statistics to test a widely used two-level model. With the high statistics we could perform two independent analyses: one based on the observed β -strength distribution within the R-matrix framework, and a second based on the extracted β -recoil broadening. The latter makes it possible to extract the Fermi and Gamow-Teller strengths up to the electron-capture region. The obtained strengths are fully consistent with the two-state isospin mixing model.
Isospin structure
Beta decay study
Beta-delayed-alpha emission
Beta strength
Fermi and Gamow Teller transitions
Författare
D. Fernández Ruiz
Consejo Superior de Investigaciones Científicas (CSIC)
M. Borge
Consejo Superior de Investigaciones Científicas (CSIC)
E. Nacher
Universitat de Valencia
Consejo Superior de Investigaciones Científicas (CSIC)
O. Tengblad
Consejo Superior de Investigaciones Científicas (CSIC)
S. Viñals
Consejo Superior de Investigaciones Científicas (CSIC)
J. Benito
Universidad Complutense de Madrid
J. A. Briz
Universidad Complutense de Madrid
Consejo Superior de Investigaciones Científicas (CSIC)
P. Figuera
Istituto Nazionale di Fisica Nucleare
L. M. Fraile
CERN
Universidad Complutense de Madrid
H. O. U. Fynbo
Aarhus Universitet
A. Gad
Student vid Chalmers
J. H. Jensen
Aarhus Universitet
Erik Asbjörn Mikkelsen Jensen
Chalmers, Fysik, Subatomär, högenergi- och plasmafysik
Aarhus Universitet
Björn Jonson
Chalmers, Fysik, Subatomär, högenergi- och plasmafysik
R. Lica
Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering
I. Marroquin
Consejo Superior de Investigaciones Científicas (CSIC)
M. Munch
Aarhus Universitet
J. S. Nielsen
Aarhus Universitet
J. D. Ovejas
Consejo Superior de Investigaciones Científicas (CSIC)
A. Perea
Consejo Superior de Investigaciones Científicas (CSIC)
K. Riisager
Aarhus Universitet
S. Sekal
CERN
University of Sciences and Technology Houari Boumediene (USTHB)
C. Sotty
Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
0370-2693 (ISSN)
Vol. 880 140791Ämneskategorier (SSIF 2025)
Subatomär fysik
DOI
10.1016/j.physletb.2026.140791