A new measurement of the intruder configuration in 12Be

Abstract

A new 11 Be(d, p) 12 Be transfer reaction experiment was carried out in inverse kinematics at 26.9A MeV, with special efforts devoted to the determination of the deuteron target thickness and of the required optical potentials from the present elastic scattering data. In addition a direct measurement of the cross section for the 0 + 2 state was realized by applying an isomer-tagging technique. The s-wave spectroscopic factors of 0.20 +0.03 −0.04 and 0.41 +0.11 −0.11 were extracted for the 0 + 1 and 0 + 2 states, respectively, in 12 Be. Using the ratio of these spectroscopic factors, together with the previously reported results for the p-wave components, the single-particle component intensities in the bound 0 + states of 12 Be were deduced, allowing a direct comparison with the theoretical predictions. It is evidenced that the ground-state configuration of 12 Be is dominated by the d-wave intruder, exhibiting a dramatic evolution of the intruding mechanism from 11 Be to 12 Be, with a persistence of the N = 8 magic number broken.

Experimental study of the effective nucleon-nucleon interaction using the F21(d,p)F22

“…In particular, 26 F levels were systematically over-bound by ∼ 30 − 40% of the total interaction strength (∼ 300 keV). An analogous situation was also observed between analog levels in the protonunbound 1s 1/2 state in 16 F relative to the bound neutron state in 16 N [13].…”

“…4(a), taken from Table I. Each calculation had a closed 16 O core and the valence particles were free to occupy all sd orbitals. A notable difference between the USDA/USDB interactions and the USD interaction is the proper reproduction of the oxygen drip line at N =16 by the former two.…”

“…The one-neutron transfer reaction is a powerful tool to study the single-particle structure of nuclei [14][15][16][17]. In the present work, one-neutron adding (d, p) reaction on 21 F is used to explore the single-particle structure of the low-lying states in 22 F. A summary of previously identified levels in 22 F, along with their possible spinparity assignments, are shown in Fig.…”

Low-lying states in Be12 using one-neutron transfer reaction

“…Using the previously measured 1p 1/2 -wave strengths in the charge-exchange reaction, the extracted values are γ 1 = 0.24 and γ 2 = 0.59 within the p − sd model space. Combining all these conditions, the intensities were deduced: α 1 = 0.19 ± 0.07, β 1 = 0.57 ± 0.07, γ 1 = 0.24 ± 0.05, α 2 = 0.39 ± 0.02, β 2 = 0.02 ± 0.02, γ 2 = 0.59 ± 0.05 [27].…”

“…Following the previous letter [27], we present here the details associated with the newly performed transfer reaction experiment to investigate the configuration of the low-lying states in 12 Be. In addition to the first two 0 + states, which are the focus of the earlier work, the results for the 2 + and 1 − states are reported here.…”