2024/11/15 by C. V. Mehl, J. N. Orce, Mehl, C. V. +65
Chemistry · Physics and Astronomy · #Advanced Chemical Physics Studies #Advanced NMR Techniques and Applications #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Nuclear physics research studies
paper · pdf · doi:10.48550/arxiv.2411.10598
openalex publication_date 2024/11/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The spectroscopic quadrupole moment of the first excited state, QS(2+1), at 1.634 MeV in 20Ne was determined from sensitive reorientation-effect Coulomb-excitation measurements using a heavy target and safe energies well below the Coulomb barrier. Particle-γ coincidence measurements were collected at iThemba LABS with a digital data-acquisition system using the \sc AFRODITE array coupled to an annular, doubled-sided silicon detector. A precise value of QS(2+1)=-0.22(2) eb was determined at backward angles in agreement with the only safe-energy measurement prior to this work, QS(2+1)=-0.23(8) eb. This result adopts 1ℏω shell-model calculations of the nuclear dipole polarizability of the 2+1 state that contributes to the effective quadrupole interaction and determination of QS(2+1). It disagrees, however, with the ideal rotor model for axially-symmetric nuclei by almost 3σ. Larger discrepancies are computed by modern state-of-the-art calculations performed in this and prior work, including \it ab initio shell model with chiral effective interactions and the multi-reference relativistic energy density functional (\sc MR-EDF) model. The intrinsic nucleon density of the 2+1 state in 20Ne calculated with the \sc MR-EDF model illustrates the presence of α clustering, which explains the largest discrepancy with the rotor model found in the nuclear chart and motivates the explicit inclusion of α clustering for full convergence of E2 collective properties.