Beta-alpha correlation in the decay of 20Na

doi:10.1016/0370-2693(77)90093-4

Physics Letters B

Volume 67, Issue 2, 28 March 1977, Pages 165-168

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Abstract

We have measured the β-α angular correlation in the allowed positron decay of ²⁰Na to the 7.42 MeV state of ²⁰Ne. The correlation is of the form $1 + a cos θ + p cos^{2} θ$ . We find $p = −0.003 ± 0.005$ in reasonable agreement with expectations based on the conserved vector current theory.

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Cited by (3)

Radiative decays of unbound levels in 20Ne
1980, Nuclear Physics, Section A
Nine levels in the range 8.7 to 12.5 MeV in ²⁰Ne have been investigated with the ¹⁶O(α, γ)²⁰Ne and ¹⁶O(α, α')¹⁶O^∗(6.13 MeV) reactions using a differentially pumped windowless gas target. Three of the levels have not been observed previously in these reactions, and new information has been obtained for most of the others. In particular, the 11.27 MeV 1⁻ level is shown to have T = 1, a result of relevance to a proposed parity violation experiment, and the analogue of the 1.97 MeV (3⁻ T = 1) level in ²⁰F is shown to lie at 12.25 MeV in ²⁰Ne rather than at 12.39 MeV as proposed previously. In addition, the 12.25 MeV level has a width Γ < 1 keV, in contrast to the value Γ ∼ 5 keV reported in other work. The electromagnetic transition rates for positive parity T = 1 states in ²⁰Ne are compared with shell-model calculations.
Measurements of the radiative widths of the first T = 1, 2+ state of 20Ne and their relationship to analog β-decays
1977, Nuclear Physics, Section A
The radiative widths for decays of the ²⁰Ne T = 1, 2⁺ (10.27 MeV) state were measured by resonance α-capture in the reaction ¹⁶O(α, γ)²⁰Ne. A special windowless gas-cell target yielded a low-background spectrum enabling six γ-branches to be observed with a Ge(Li) detector. The six branches correspond to decays from the 10.27 MeV level to the following levels: 2⁺(7.83 MeV), 2⁺(7.42 MeV), 3⁻(5.62 MeV), 2⁻(4.97 MeV), 2⁺(1.63 MeV) and 0⁺(g.s.). The branching ratios and radiative widths Γ_γ to these levels are: 7.83 MeV [(0.22 ± 0.06)%, 0.008 ± 0.002 eV], 7.42 MeV [(6.9 ± 0.4)%, 0.31 ± 0.04 eV], 5.62 MeV [(2.1 ± 0.2)%, 0.097 ± 0.014 eV], 4.97 MeV [(1.3 ± 0.1)%, 0.060 ± 0.008 eV], 1.63 MeV [(88.9 ± 0.5)%, 4.08 ± 0.43 eV] and 0.0 MeV [(0.64 ± 0.14)%, 0.029 ± 0.008 eV]. The radiative widths to the 1.63 MeV and 7.42 MeV levels are used to determine the CVC predictions of the weak magnetism form factors and their effects on certain β-decay observables are evaluated.
Direct observation of the exotic β-γ-α decay mode in the Tz=-1 nucleus Na 20
2021, Physical Review C

^☆: Work supported in part by the National Science Foundation under grant No. MP571-03445.

¹: Present address: Department of Physics, Stanford University, Stanford, California 94305, USA.

²: Present address: Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.

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Physics Letters B

Abstract

References (15)

Rev. Mod. Phys.

Phys. Rev. Lett.

Phys. Rev.

Phys. Rev. Lett.

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Phys. Rev.

Cited by (3)

Radiative decays of unbound levels in <sup>20</sup>Ne

Measurements of the radiative widths of the first T = 1, 2<sup>+</sup> state of <sup>20</sup>Ne and their relationship to analog β-decays

Direct observation of the exotic β-γ-α decay mode in the Tz=-1 nucleus Na 20

Beta-alpha correlation in the decay of 20Na☆

Abstract

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Beta-alpha correlation in the decay of ²⁰Na☆