title: Breakdown of the Z=8 shell closure in unbound 12O and its mirror symmetry.
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.
authors.affiliation: Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Iwasaki
authors.forename: D
authors.initials: D
authors.lastname: Beaumel
authors.forename: L
authors.initials: L
authors.lastname: Nalpas
authors.forename: E
authors.initials: E
authors.lastname: Pollacco
authors.forename: M
authors.initials: M
authors.lastname: Assié
authors.forename: H
authors.initials: H
authors.lastname: Baba
authors.forename: Y
authors.initials: Y
authors.lastname: Blumenfeld
authors.forename: N
authors.initials: N
authors.lastname: De Séréville
authors.forename: A
authors.initials: A
authors.lastname: Drouart
authors.forename: S
authors.initials: S
authors.lastname: Franchoo
authors.forename: A
authors.initials: A
authors.lastname: Gillibert
authors.forename: J
authors.initials: J
authors.lastname: Guillot
authors.forename: F
authors.initials: F
authors.lastname: Hammache
authors.forename: N
authors.initials: N
authors.lastname: Keeley
authors.forename: V
authors.initials: V
authors.lastname: Lapoux
authors.forename: F
authors.initials: F
authors.lastname: Maréchal
authors.forename: S
authors.initials: S
authors.lastname: Michimasa
authors.forename: X
authors.initials: X
authors.lastname: Mougeot
authors.forename: I
authors.initials: I
authors.lastname: Mukha
authors.forename: H
authors.initials: H
authors.lastname: Okamura
authors.forename: H
authors.initials: H
authors.lastname: Otsu
authors.forename: A
authors.initials: A
authors.lastname: Ramus
authors.forename: P
authors.initials: P
authors.lastname: Roussel-Chomaz
authors.forename: H
authors.initials: H
authors.lastname: Sakurai
authors.forename: J-A
authors.initials: JA
authors.lastname: Scarpaci
authors.forename: O
authors.initials: O
authors.lastname: Sorlin
authors.forename: I
authors.initials: I
authors.lastname: Stefan
authors.forename: M
authors.initials: M
authors.lastname: Takechi