Year: 2026
Type: preprint
Abstract: High-resolution in-beam $γ$-ray spectroscopy of $^{53}$Ca was performed at the Radioactive Isotope Beam Factory (RIBF) at RIKEN. Excited states in $^{53}$Ca were populated via one-neutron and one-proton removal reactions from a $^{55}$Sc radioactive beam, and the emitted $γ$ rays were detected using the HiCARI hybrid germanium detector array. The lifetime of the first excited $5/2^{-}$ state in $^{53}$Ca was measured for the first time through an analysis of Doppler-roadened $γ$-ray line shapes arising from relativistic recoil velocities. A lifetime of $τ = 11.3_{-11.3}^{+5.3(stat)+3(sys)}$ ps was deduced, corresponding to a reduced transition probability of $B(E2;5/2^{-}{\rightarrow}1/2^{-}) > 2.6 e^{2}fm^{4}$ at the 1$σ$ level, with a best-fit value of $4.5 e^{2}fm^{4}$. The measured transition strength is compared with state-of-the-art shell-model and ab initio calculations, providing a stringent benchmark for shell-model Hamiltonians and effective charges and modern ab initio descriptions of the neutron-rich calcium isotopes approaching the potential $N$ = 40 shell closure.
Source: arXiv (Cornell University)
Authors: Chen, S., Petri, M., Paschalis, S., Crawford, H. L., Doornenbal, P., Taniuchi, R., Wimmer, K., Brown, B. A., Holt, J. D., Hu, B. S., Miyagi, T., Otsuka, T., Tsunoda, Y., Aoi, N., Baba, H., Bentley, M., Browne, F., Campbell, C., Chen, Z., Crane, R., de Witte, H., Fallon, P., Fransen, C., Hess, H., Ideguchi, E., Iwazaki, S., Kim, J., Kohda, A., Koiwai, T., Marshall, W., Mauss, B., Moon, B., Parry, T., Reiter, P., Sakurai, H., Suzuki, D., Tetley, L., Thiel, S., Yamamoto, Y.
Institutions: University of York, Lawrence Berkeley National Laboratory, RIKEN Nishina Center, Facility for Rare Isotope Beams, Michigan State University, TRIUMF, McGill University, University of Tsukuba, Center for Computational Sciences, University of Tsukuba, Research Center for Nuclear Physics, The University of Osaka, The University of Osaka, GSI Helmholtz Centre for Heavy Ion Research, KU Leuven, University of Cologne, Korea University, The University of Tokyo, Institute for Basic Science, University of Surrey
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Western Canada Research Grid, National Research Foundation, Deutsche Forschungsgemeinschaft, University of Tokyo, Institute for Basic Science, Alliance de recherche numérique du Canada, Office of Science, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council, Japan Society for the Promotion of Science, RIKEN, Nuclear Physics, Exploratory Research for Advanced Technology, Argonne National Laboratory, Lawrence Berkeley National Laboratory
Awards: G1079818582, G1143651532, G1286236842, G1313983767, G138487567, G1863003419, G2638771445, Nuclear Physics Consolidated Grant 21-24 - University of York, G2821925151, A high-resolution gamma-ray tracking detector for in-beam spectroscopy of unstable nuclei, G3685081974, G3705047715, G4061288673, G4071980169, G419881185, G4267506587, G42916606, Study of rapid proton capture and X-ray burster by energy-degraded RI beams, Large-scale ab initio calculations of sd-shell nuclei and many-body correlations, G4501827968, G4547971943, G498139845, NP Consolidated Grant York, G6044734838, G638836682, G6652958823, G7082598299, G7354628648, Nuclear Structure Theory and its Applications to Nuclear Properties, Astrophysics and Fundamental Physics, Nuclear matrix elements of heavy nuclei from first principles, Description of collective motion in medium-heavy nuclei by the collaboration of ab initio theory and phenomenology, Nuclear Physics Consolidated Grant, G8211577190, Study of phase transitions in femto-scale quantum systems by energy-degraded RI beams, G9000240326
OpenAlex ID: W7213995729