On neutron-deficient isotopes of light nuclei and the phenomena of proton and two-proton radioactivity

Goldansky, V.I.

doi:10.1016/0029-5582(60)90258-3

Cited by 341 publications

(299 citation statements)

References 3 publications

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“…Unsurprisingly, beyond the dripline, novel structures can give rise to exotic decay paths. Two-proton decay was first theorized in 1960 [3]. When two nucleons decay from a core, there are three possible mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Three-body model for the two-neutron emission ofBe16

2017

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Background: While diproton decay was first theorized in 1960 and first measured in 2002, it was first observed only in 2012.The measurement of 14 Be in coincidence with two neutrons suggests that 16 Be does decay through the simultaneous emission of two strongly correlated neutrons.Purpose: In this work, we construct a full three-body model of 16 Be (as 14 Be + n + n) in order to investigate its configuration in the continuum and in particular the structure of its ground state.Method: In order to describe the three-body system, effective n-14 Be potentials were constructed, constrained by the experimental information on 15 Be. The hyperspherical R-matrix method was used to solve the three-body scattering problem, and the resonance energy of 16 Be was extracted from a phase shift analysis.Results: In order to reproduce the experimental resonance energy of 16 Be within this three-body model, a three-body interaction was needed. For extracting the width of the ground state of 16 Be, we use the full width at half maximum of the derivative of the three-body phase shifts and the width of the three-body elastic scattering cross section. Conclusions:Our results confirm a dineutron structure for 16 Be, dependent on the internal structure of the subsystem 15 Be.

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Section: Introductionmentioning

confidence: 99%

Three-body model for the two-neutron emission ofBe16

2017

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“…From near to beyond the drip-lines, the nuclear force is no longer able to bind the interacting nucleons leading to instability of nuclei with respect to nucleon emission. On the proton-rich side of the chart of nuclides, the pairing force may lead to a situation where a drip-line nucleus is bound with respect to single proton emission but unbound to two-proton emission [1,2]. Several types of two-proton emitters have been observed.…”

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confidence: 99%

Spectroscopy of 18Na: Bridging the two-proton radioactivity of 19Mg

Assié¹,

Santos²,

Davinson³

et al. 2012

Physics Letters B

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The unbound nucleus 18 Na, the intermediate nucleus in the two-proton radioactivity of 19 Mg, was studied by the measurement of the resonant elastic scattering reaction 17 Ne(p, 17 Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix analysis of the excitation function. Using these new results, we show that the lifetime of the 19 Mg radioactivity can be understood assuming a sequential emission of two protons via low energy tails of 18 Na resonances. From near to beyond the drip-lines, the nuclear force is no longer able to bind the interacting nucleons leading to instability of nuclei with respect to nucleon emission. On the proton-rich side of the chart of nuclides, the pairing force may lead to a situation where a drip-line nucleus is bound with respect to single proton emission but unbound to two-proton emission [1,2]. Several types of two-proton emitters have been observed. On the one hand, there are the short-lived (τ 1/2 ≤ 10 −18 s) light nuclei such as 6 [6] when assuming only d-wave single-particle states in the low-lying structure of 18 Na and thus a dominant d 2 single-particle configuration for 19 Mg. Theoretical calculations of properties of 19 Mg depend strongly on the assumption made about the structure of 18 Na and its mirror nucleus. In this letter, we investigate both experimentally and theoretically the low lying spectrum of 18 Na. We strongly refine the knowledge about the lowlying spectrum of 18 Na and find that there are also lowlying s-wave states. These states should strongly boost the expected two-proton width.On the theoretical side, the structure of 18 Na has been predicted assuming a core of 17 Ne + proton structure [6] or by coupling a neutron hole to the lowest states in 19 Na [7]. In both cases, the low-lying structure of 18 Na is found to have d-wave configuration. In the following, another theoretical approach is described and predicts also low lying s-wave states. The dimensionless reduced widths θ 2 (sometimes called spectroscopic factors) where estimated with the shell model. The values shown in Tab. I were obtained with the OXBASH code [8] and the ZBM interaction [9] in the 1p 1/2 , 1d 5/2 and 2s 1/2 shells space. It predicts that the first six low lying states can be described mainly (with θ 2 > 0.5) by single particle con-

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“…After the prediction of the 2p radioactivity by Goldansky in 1960 [1], significant theoretical work was devoted to identify the best candidates for the observation of this process. This task required precise predictions of masses for nuclei in the proton-drip line region.…”

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confidence: 99%