Above threshold s-wave resonances illustrated by the 1/2${}^{+}$ states in ${}^9$Be and ${}^9$B

Abstract

We solve the persistent problem of the structure of the lowest $1/2^{+}$ resonance in ${}^9$Be which is important to bridge the A=8 gap in nucleosynthesis in stars. We show that the state is a genuine three-body resonance even though it decays entirely into neutron-${}^8$Be relative s-waves. The necessary barrier is created by "dynamical" evolution of the wave function as the short-distance $\alpha$-${}^5$He structure is changed into the large-distance n-${}^8$Be structure. This decay mechanism leads to a width about two times smaller than table values. The previous interpretations as a virtual state or a two-body resonance are incorrect. The isobaric analog 1/2${}^{+}$ state in ${}^9$B is found to have energy and width in the vicinity of 2.0 MeV and 1.5 MeV, respectively. We also predict another 1/2${}^{+}$ resonance in ${}^9$B with similar energy and width.

To be published in Physics Letters B

References in corpus (5)

• Structure of low-lying 12C-resonances
• Momentum distributions of $\alpha$-particles from decaying low-lying ${}^{12}$C-resonances
• Three-body structure of low-lying 12Be states
• Cluster sum rules for three-body systems with angular-momentum dependent interactions
• Origin of three-body resonances

Cited by in corpus (15)

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• Direct and sequential radiative three-body reaction rates at low temperatures
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• The virtual-state character of the {9}^Be 1/2^+ state in the {9}^Be(γ,n){8}^Be reaction
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• Photodisintegration cross section of ${}^9$Be up to 16 MeV in the $\alpha$ + $\alpha$ + n three-body model
• Properties of the first excited state of 9Be derived from (gamma,n) and (e,e') reactions
• Three-body properties of low-lying ${}^{12}$Be resonances
• Few-body decay and recombination in nuclear astrophysics
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• Momentum distributions from three-body decaying 9Be and 9B resonances
• Studies of quasiclassical approach applicability to true three-body decays