https://doi.org/10.1140/epja/s10050-020-00133-9
Regular Article - Experimental Physics
Low-energy super Gamow–Teller (LeSGT) and anti-LeSGT transitions
Hindered “allowed 
decay” of 
C as an anti-LeSGT transition
1
Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka, 567-0047, Japan
2
Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043, Japan
3
Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
4
Center for Nuclear Study, The University of Tokyo, Hongo, Bunkyo, Tokyo, 113-0033, Japan
* e-mail: fujita@rcnp.osaka-u.ac.jp
Received:
6
January
2020
Accepted:
29
March
2020
Published online:
19
May
2020
The LS-closed doubly-magic nuclei (DMN) 
, 
, and 
behave as inert cores for Gamow–Teller (GT) excitations. It is known that GT transition strengths from nuclei with DMN + identical two-nucleon particles (2p) to nuclei with DMN + proton-neutron particles (
-
), i.e., 
, 
(or 
)
, and 
(or 
)
, concentrate in the lowest GT states called the Low-energy Super GT (LeSGT) states. On the other hand, we notice that the GT strengths from nuclei with DMN + identical two-nucleon holes (2h) to nuclei with DMN + proton-neutron holes (
-
), i.e., 
(or 
)
, and 
(or 
)
, concentrate in the second GT states. Accordingly, the lowest GT states, which can be called the anti-LeSGT states, are poorly excited. We find that this seesaw-like GT strength distributions in the 2p and 2h systems are the key to understand the hindered decay of C. The origin of the “Seesaw Mechanism” is analyzed by means of shell-model (SM) calculations.
© Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2020
