title: Decay and Fission Hindrance of Two- and Four-Quasiparticle K Isomers in ^{254}Rf.
abstract: Two isomers decaying by electromagnetic transitions with half-lives of 4.7(1.1) and 247(73) μs have been discovered in the heavy ^{254}Rf nucleus. The observation of the shorter-lived isomer was made possible by a novel application of a digital data acquisition system. The isomers were interpreted as the K^{π}=8^{-}, ν^{2}(7/2^{+}[624],9/2^{-}[734]) two-quasineutron and the K^{π}=16^{+}, 8^{-}ν^{2}(7/2^{+}[624],9/2^{-}[734])⊗8^{-}π^{2}(7/2^{-}[514],9/2^{+}[624]) four-quasiparticle configurations, respectively. Surprisingly, the lifetime of the two-quasiparticle isomer is more than 4 orders of magnitude shorter than what has been observed for analogous isomers in the lighter N=150 isotones. The four-quasiparticle isomer is longer lived than the ^{254}Rf ground state that decays exclusively by spontaneous fission with a half-life of 23.2(1.1) μs. The absence of sizable fission branches from either of the isomers implies unprecedented fission hindrance relative to the ground state.
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: David
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: D
authors.initials: D
authors.lastname: Seweryniak
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: F G
authors.initials: FG
authors.lastname: Kondev
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Gates
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Gregorich
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: I
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: M
authors.initials: M
authors.lastname: Albers
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: M
authors.initials: M
authors.lastname: Alcorta
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: B B
authors.initials: BB
authors.lastname: Back
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: B
authors.initials: B
authors.lastname: Baartman
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: P F
authors.initials: PF
authors.lastname: Bertone
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Bernstein
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Campbell
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Carpenter
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.|Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Chiara
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Clark
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: M
authors.initials: M
authors.lastname: Cromaz
authors.affiliation: School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: D T
authors.initials: DT
authors.lastname: Doherty
authors.affiliation: Department of Nuclear Physics, R.S.P.E., Australian National University, Canberra A.C.T. 2601, Australia.
authors.forename: G D
authors.initials: GD
authors.lastname: Dracoulis
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: N E
authors.initials: NE
authors.lastname: Esker
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: P
authors.initials: P
authors.lastname: Fallon
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: O R
authors.initials: OR
authors.lastname: Gothe
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Greene
authors.affiliation: Department of Physics, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
authors.forename: P T
authors.initials: PT
authors.lastname: Greenlees
authors.affiliation: United States Naval Academy, Annapolis, Maryland 21402, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hartley
authors.affiliation: CSNSM, IN2P3-CNRS, F-91405 Orsay Campus, France.
authors.forename: K
authors.initials: K
authors.lastname: Hauschild
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Hoffman
authors.affiliation: Department of Physics, University of Massachusetts, Lowell, Massachusetts 01854, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Hota
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: R V F
authors.initials: RV
authors.lastname: Janssens
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Khoo
authors.affiliation: Department of Physics, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Konki
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Kwarsick
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: T
authors.initials: T
authors.lastname: Lauritsen
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: A O
authors.initials: AO
authors.lastname: Macchiavelli
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Mudder
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: C
authors.initials: C
authors.lastname: Nair
authors.affiliation: Department of Physics, University of Massachusetts, Lowell, Massachusetts 01854, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: J
authors.initials: J
authors.lastname: Rissanen
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Rogers
authors.affiliation: Department of Physics, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Ruotsalainen
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: G
authors.initials: G
authors.lastname: Savard
authors.affiliation: Department of Physics, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Stolze
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wiens
authors.affiliation: Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: S
authors.initials: S
authors.lastname: Zhu