Structure and three-body decay ofBe9resonances

Abstract

The complex-rotated hyperspherical adiabatic method is used to study the decay of low-lying 9 Be resonances into one neutron and two α particles. We investigate the six resonances above the breakup threshold and below 6 MeV: 1/2 ± , 3/2 ± , and 5/2 ± . The short-distance properties of each resonance are studied, and the different angular momentum and parity configurations of the 8 Be and 5 He two-body substructures are determined. We compute the branching ratio for sequential decay via the 8 Be ground state, which qualitatively is consistent with measurements. We extract the momentum distributions after decay directly into the three-body continuum from the large-distance asymptotic structures. The kinematically complete results are presented as Dalitz plots as well as projections on given neutron and α energy. The distributions are discussed and, in most cases, found to agree with available experimental data.

Impurity effects of theΛparticle on the2αcluster states ofBe9andIsaka1, Kimura2 2015Phys. Rev. C22190View full textAdd to dashboardCite

“…In 9 Be, we focus on the ground (3/2 − ) and 1/2 + states. The 1/2 + state is considered to be a virtual state [33,34] or a resonance state [35,36] with the well-developed α + α + n cluster structure. By using the original parameter set of the Gogny D1S force, the excitation energy of the 1/2 + state E x ( 9 Be; 1/2 + ) is calculated as 2.00 MeV within the bound state approximation, whereas the central value of the observed excitation energy is E exp.…”

“…[33,34], the virtual-state character of this state was shown, while the authors of Refs. [35,36] discussed this state as a three-body resonance state. It is expected that study of 10 Λ Be provides a new insight to the nature of the 1/2 + state, because a Λ particle will bound this state and spectroscopic information could be obtained.…”

Photodisintegration cross section ofBe9up to 16 MeV in theα + α + nthree-body model

“…The photodisintegration cross section of 9 Be shows various features in different energy regions. The cross section in a lowenergy region has been measured to deduce a production rate of 9 Be from the astrophysical point of view [1][2][3][4][5][6][7].…”

“…The cross section in a lowenergy region has been measured to deduce a production rate of 9 Be from the astrophysical point of view [1][2][3][4][5][6][7]. In the lowenergy region up to E γ = 6 MeV, the cross section has been observed to come from the electromagnetic transitions into the excited states of 9 Be, and theoretically, has been studied within the α + α + n three-body model [8][9][10][11].…”

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The photodisintegration of 9 Be in the energy region lower than E γ = 16 MeV is investigated by using the α + α + n three-body model and the complex scaling method. The cross section exhibits two aspects in two different energy regions.

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