2025/06/03 by Ngwetsheni, C., Orce, J. N., Navrátil, P. +14
#Data Analysis #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Statistics and Probability (physics.data-an)
paper · doi:10.48550/arxiv.2506.03236
A Coulomb-excitation study of the high-lying first excited state at 4.439 MeV in the nucleus 12C has been carried out using the 208Pb(12C,12C^*)208Pb^* reaction at 56 MeV and the \sc Q3D magnetic spectrograph at the Maier-Leibnitz Laboratorium in Munich. High-statistics achieved with an average beam intensity of approximately 1011 ions/s together with state-of-the-art \it ab initio calculations of the nuclear dipole polarizability permitted the accurate determination of the spectroscopic quadrupole moment, QS(21+) = +0.076(30)~eb, in agreement with previous measurements. Combined with previous work, a weighted average of QS(21+) = +0.090(14) eb is determined, which includes the re-analysis of a similar experiment by Vermeer and collaborators, QS(21+) = +0.103(20)~eb. Such a large oblate deformation challenges modern nuclear theory and emphasizes the need of α clustering and associated triaxiality effects for full convergence of E2 collective properties.