Restoration of the n=82 shell gap from direct mass measurements of 132,134Sn.
A high-precision direct Penning trap mass measurement has revealed a 0.5-MeV deviation of the binding energy of (134)Sn from the currently accepted value. The corrected mass assignment of this neutron-rich nuclide restores the neutron-shell gap at N=82, previously considered to be a case of "shell quenching." In fact, the new shell gap value for the short-lived (132)Sn is larger than that of the doubly magic (48)Ca which is stable. The N=82 shell gap has considerable impact on fission recycling during the r process. More generally, the new finding has important consequences for microscopic mean-field theories which systematically deviate from the measured binding energies of closed-shell nuclides.
Dworschak
M
M
GSI, Planckstrasse 1, 64291 Darmstadt, Germany. m.dworschak.gsi.de
Audi
G
G
Blaum
K
K
Delahaye
P
P
George
S
S
Hager
U
U
Herfurth
F
F
Herlert
A
A
Kellerbauer
A
A
Kluge
H-J
HJ
Lunney
D
D
Schweikhard
L
L
Yazidjian
C
C