| 1. |
- Mukha, I., et al.
(author)
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Observation and Spectroscopy of New Proton-Unbound Isotopes Ar-30 and Cl-29: An Interplay of Prompt Two-Proton and Sequential Decay
- 2015
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In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 115:20, s. 7-
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Journal article (peer-reviewed)abstract
- Previously unknown isotopes Ar-30 and Cl-29 have been identified by measurement of the trajectories of their in-flight decay products S-28 + p + p and S-28 + p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of Ar-30 and Cl-29 were found at 2.25(-0.10)(+0.15) and 1.8 +/- 0.1 MeV above the two-and one-proton thresholds, respectively. The lowest states in Ar-30 and Cl-29 point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the Ar-30 ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of Ar-30*(2(+)) has been obtained by detecting two decay branches into the ground and first-excited states of the S-28 fragment.
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| 2. |
- Golubkova, T. A., et al.
(author)
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Transition from direct to sequential two-proton decay in s–d shell nuclei
- 2016
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 762, s. 263-270
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Journal article (peer-reviewed)abstract
- The transition between different mechanisms of two-proton decay in exotic nuclei and the governing physical conditions are generally studied. To perform this large-scale survey, the direct-decay model, which is widely used, was improved by generalizing the semi-analytical approaches used before. The improved model provides a flawless phenomenological description of three-body correlations in 2p decays, as is demonstrated by several examples of decays of low-lying states in 16Ne. Different transition mechanisms are shown to occur beyond the proton dripline for s–d shell nuclei. It is found that the transition dynamics of 2p-emitters allows the extraction of the width of the ground-state resonance of the core+p subsystem. The practical application of the method is illustrated by determining properties of the 14F ground state derived from the Ne15?O13+2p decay data, and of the 29Cl ground state derived from the Ar30?S28+2p decay data.
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| 3. |
- Grigorenko, L. V., et al.
(author)
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Decay mechanism and lifetime of Kr-67
- 2017
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In: Physical Review C. - 2469-9985 .- 2469-9993. ; 95:2
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Journal article (peer-reviewed)abstract
- The lifetime of the recently discovered 2p emitter Kr-67 was found to be considerably below the lower limit predicted theoretically. This communication addresses this issue. Different separation energy systematics are analyzed and different mechanisms for 2p emission are evaluated. We find that the most plausible reason for this disagreement is the decay mechanism of 67Kr, which is not "true 2p" emission but rather "transitional dynamics" on the borderline between true 2p and sequential 2p decay mechanisms. If this is correct, this imposes stringent limits of E-r = 1.35-1.42 MeV on the ground-state energy of Br-66 relative to the Se-65-p threshold.
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| 4. |
- Grigorenko, L. V., et al.
(author)
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Thomas-Ehrman effect in a three-body model: The Ne-16 case
- 2015
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 91:2, s. article no. 024325 -
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Journal article (peer-reviewed)abstract
- The dynamic mechanism of the Thomas-Ehrman shift in three-cluster systems is studied by using the example of Ne-16 and C-16 isobaric mirror partners. We predict configuration mixings for 0(+) and 2(+) states in Ne-16 and C-16. Large isospin symmetry breaking on the level of wave function component weights is demonstrated for these states and discussed as a three-body mechanism of the Thomas-Ehrman shift. It is shown that the description of the Coulomb displacement energies requires consistency among three parameters: the Ne-16 decay energy ET, the F-15 ground-state energy E-r, and the configuration mixing parameters for the Ne-16 and (16)C0(+) and 2(+) states. Based on this analysis we infer the (15)F1/2(+) ground-state energy to be E-r = 1.39-1.42 MeV.
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