Breakdown of the Z=8 shell closure in unbound 12O and its mirror symmetry

Authors :: D, Suzuki
H, Iwasaki
D, Beaumel
L, Nalpas
E, Pollacco
M, Assié
H, Baba
Y, Blumenfeld
N, De Séréville
A, Drouart
S, Franchoo
A, Gillibert
J, Guillot
F, Hammache
N, Keeley
V, Lapoux
F, Maréchal
S, Michimasa
X, Mougeot
I, Mukha
H, Okamura
H, Otsu
A, Ramus
P, Roussel-Chomaz
H, Sakurai
J-A, Scarpaci
O, Sorlin
I, Stefan
M, Takechi
Source :: Physical review letters. 103(15)
Publication Year :: 2009
Abstract: An excited state in the proton-rich unbound nucleus 12O was identified at 1.8(4) MeV via missing-mass spectroscopy with the 14O(p,t) reaction at 51 AMeV. The spin-parity of the state was determined to be 0+ or 2+ by comparing the measured differential cross sections with distorted-wave calculations. The lowered location of the excited state in 12O indicates the breakdown of the major shell closure at Z=8 near the proton drip line. This demonstrates the persistence of mirror symmetry in the disappearance of the magic number 8 between 12O and its mirror partner 12Be.

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