title: Strong Neutron-γ Competition above the Neutron Threshold in the Decay of ^{70}Co.
abstract: The β-decay intensity of ^{70}Co was measured for the first time using the technique of total absorption spectroscopy. The large β-decay Q value [12.3(3) MeV] offers a rare opportunity to study β-decay properties in a broad energy range. Two surprising features were observed in the experimental results, namely, the large fragmentation of the β intensity at high energies, as well as the strong competition between γ rays and neutrons, up to more than 2 MeV above the neutron-separation energy. The data are compared to two theoretical calculations: the shell model and the quasiparticle random phase approximation (QRPA). Both models seem to be missing a significant strength at high excitation energies. Possible interpretations of this discrepancy are discussed. The shell model is used for a detailed nuclear structure interpretation and helps to explain the observed γ-neutron competition. The comparison to the QRPA calculations is done as a means to test a model that provides global β-decay properties for astrophysical calculations. Our work demonstrates the importance of performing detailed comparisons to experimental results, beyond the simple half-life comparisons. A realistic and robust description of the β-decay intensity is crucial for our understanding of nuclear structure as well as of r-process nucleosynthesis.
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: A
authors.initials: A
authors.lastname: Spyrou
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: S N
authors.initials: SN
authors.lastname: Liddick
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: F
authors.initials: F
authors.lastname: Naqvi
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Crider
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Dombos
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9234, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Bleuel
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Brown
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: A
authors.initials: A
authors.lastname: Couture
authors.affiliation: Department of Physics, University of Oslo, NO-0316 Oslo, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Crespo Campo
authors.affiliation: Department of Physics, University of Oslo, NO-0316 Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Guttormsen
authors.affiliation: Department of Physics, University of Oslo, NO-0316 Oslo, Norway.
authors.forename: A C
authors.initials: AC
authors.lastname: Larsen
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: R
authors.initials: R
authors.lastname: Lewis
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: P
authors.initials: P
authors.lastname: Möller
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: S
authors.initials: S
authors.lastname: Mosby
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Mumpower
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.|Central Michigan University, Mt. Pleasant, Michigan 48859, USA.
authors.forename: G
authors.initials: G
authors.lastname: Perdikakis
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Prokop
authors.affiliation: Department of Physics, University of Oslo, NO-0316 Oslo, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Renstrøm
authors.affiliation: Department of Physics, University of Oslo, NO-0316 Oslo, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Siem
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.|Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.|Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Quinn
authors.affiliation: Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ-180 00 Prague 8, Czech Republic.
authors.forename: S
authors.initials: S
authors.lastname: Valenta