Simultaneous impacts of nuclear shell structure and collectivity on $\beta$-decay: evidence from $^{80}$Ga$_{49}$
R Li
(1)
,
D Verney
(1)
,
G de Gregorio
,
R Mancino
,
I Matea
(1)
,
L Coraggio
,
N Itaco.
,
M.N Harakeh
,
C Delafosse
(1)
,
F Didierjean
(2)
,
L.A Ayoubi
(1)
,
H. Al Falou
,
G Benzoni
,
F Le Blanc
(1)
,
V Bozkurt
,
M Ciemała
,
I Deloncle
(1)
,
M Fallot
(3)
,
C Gaulard
(1)
,
A Gottardo
,
V Guadilla
(3)
,
J Guillot
(1)
,
K Hadyńska-Klęk
,
F Ibrahim
(1)
,
N Jovancevic
(1)
,
A Kankainen
,
M Lebois
(1)
,
T Martínez
,
P Napiorkowski
,
B Roussiere
(1)
,
Yu.G Sobolev
,
I Stefan
(1)
,
S Stukalov
,
D Thisse
(1)
,
G Tocabens
(1)
G de Gregorio
- Fonction : Auteur
R Mancino
- Fonction : Auteur
L Coraggio
- Fonction : Auteur
N Itaco.
- Fonction : Auteur
M.N Harakeh
- Fonction : Auteur
H. Al Falou
- Fonction : Auteur
G Benzoni
- Fonction : Auteur
V Bozkurt
- Fonction : Auteur
M Ciemała
- Fonction : Auteur
A Gottardo
- Fonction : Auteur
K Hadyńska-Klęk
- Fonction : Auteur
A Kankainen
- Fonction : Auteur
T Martínez
- Fonction : Auteur
P Napiorkowski
- Fonction : Auteur
Yu.G Sobolev
- Fonction : Auteur
S Stukalov
- Fonction : Auteur
Résumé
The Gamow-Teller strength distribution covering the entire $\beta$-decay window, up to 10.312(4) MeV, of $^{80g+m}$Ga was measured for the first time in photo-fission of UC$_x$ induced by 50 MeV electron beam. The new data show significant enhancement in the high-energy region with a jump-structure. Simultaneously, the $\gamma$ de-exciting behavior of $\beta$-populated states presents a competition between de-excitation to 2$_1^+$ [$\beta_2$ = 0.155(9)] and to 2$_2^+$ [$\beta_2$ = 0.053$_{0.009}^{0.008}$)] in $^{80}$Ge. Based on these facts and combined with a realistic shell model calculation and systematic analysis of logft ratio between precursor $\beta$-decay to 2$_2^+$ and to 2$_1^+$ of Ga isotopes, we conclude that these phenomena evidence simultaneous impacts of nuclear shell structure and collectivity on B(GT) and its distribution and, therefore, the half-life of the precursor. These data prove that the nucleus as a multi-nucleon correlated quantum system reacts as a whole when $\beta$-decay occurs in contrast to simple single-particle excitation. Additionally, the comparison with the theoretical results evidence how challenging is the description of the experimental data obtained, and render this experimental outcome a sound test for the theoretical models.