Testing ab initio nuclear structure in neutron-rich nuclei: Lifetime measurements of second 2(+) state in C-16 and O-20



Ciemala, M, Ziliani, S, Crespi, FCL, Leoni, S, Fornal, B, Maj, A, Bednarczyk, P, Benzoni, G, Bracco, A, Boiano, C
et al (show 84 more authors) (2020) Testing ab initio nuclear structure in neutron-rich nuclei: Lifetime measurements of second 2(+) state in C-16 and O-20. Physical Review C: Nuclear Physics, 101 (2).

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Abstract

To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2+ state in neutron-rich 20O,τ(2+2)=150+80−30fs, and an estimate for the lifetime of the second 2+ state in 16C have been obtained for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds of femtoseconds range by analyzing the Doppler-shifted γ-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction 18O(7.0MeV/u)+181Ta. The requested sensitivity could only be reached owing to the excellent performances of the Advanced γ-Tracking Array AGATA, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The experimental lifetimes agree with predictions of ab initio calculations using two- and three-nucleon interactions, obtained with the valence-space in-medium similarity renormalization group for 20O and with the no-core shell model for 16C. The present measurement shows the power of electromagnetic observables, determined with high-precision γ spectroscopy, to assess the quality of first-principles nuclear structure calculations, complementing common benchmarks based on nuclear energies. The proposed experimental approach will be essential for short lifetime measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense beams, produced by Isotope Separation On-Line (ISOL) techniques, become available.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 16 Apr 2020 13:02
Last Modified: 23 Nov 2021 03:10
DOI: 10.1103/PhysRevC.101.021303
Open Access URL: https://journals.aps.org/prc/abstract/10.1103/Phys...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3083477