Investigation of the Δn = 0 selection rule in Gamow-Teller transitions : The β-decay of 207Hg
Berry, T. A., Podolyák, Z., Carroll, R. J., Lică, R., Grawe, H., Timofeyuk, N. K., . . . De Witte, H. (2019). Investigation of the Δn = 0 selection rule in Gamow-Teller transitions : The β-decay of 207Hg. Physics Letters B, 793, 271-275. doi:10.1016/j.physletb.2019.04.039
Published inPhysics Letters B
Lică, R. |
Kuti, I. |
Lund, M. |
Nae, S. |
Niţă, C. |
Warr, N. |
© 2019 The Authors. Published by Elsevier B.V.
Gamow-Teller β decay is forbidden if the number of nodes in the radial wave functions of the initial and final states is different. This Δn = 0 requirement plays a major role in the β decay of heavy neutron-rich nuclei, affecting the nucleosynthesis through the increased half-lives of nuclei on the astrophysical r-process pathway below both Z = 50 (for N > 82) and Z = 82 (for N >126). The level of forbiddenness of the Δn = 1ν1g9/2 → π0g7/2 transition has been investigated from the β− decay of the ground state of 207Hg into the single-proton-hole nucleus 207Tl in an experiment at the ISOLDE Decay Station. From statistical observational limits on possible γ-ray transitions depopulating the π0g7/2−1 state in 207Tl, an upper limit of 3.9 × 10−3% was obtained for the probability of this decay, corresponding to log ft > 8.8 within a 95% confidence limit. This is the most stringent test of the Δn = 0 selection rule to date.