학술논문
Testing ab initio nuclear structure in neutron-rich nuclei: lifetime measurements of second 2+ states in 16C and 20O
Document Type
Working Paper
Author
Ciemala, M.; Ziliani, S.; Crespi, F. C. L.; Leoni, S.; Fornal, B.; Maj, A.; Bednarczyk, P.; Benzoni, G.; Bracco, A.; Boiano, C.; Bottoni, S.; Brambilla, S.; Bast, M.; Beckers, M.; Braunroth, T.; Camera, F.; Cieplicka-Orynczak, N.; Clement, E.; Coelli, S.; Dorvaux, O.; Erturk, S.; de France, G.; Fransen, C.; Goldkuhle, A.; Grebosz, J.; Harakeh, M. N.; Iskra, L. W.; Jacquot, B.; Karpov, A.; Kicinska-Habior, M.; Kim, Y.; Kmiecik, M.; Lemasson, A.; Lenzi, S. M.; Lewitowicz, M.; Li, H.; Matea, I.; Mazurek, K.; Michelagnoli, C.; Matejska-Minda, M.; Million, B.; Muller-Gatermann, C.; Nanal, V.; Napiorkowski, P.; Napoli, D. R.; Palit, R.; Rejmund, M.; Schmitt, Ch.; Stanoiu, M.; Stefan, I.; Vardaci, E.; Wasilewska, B.; Wieland, O.; Zieblinski, M.; Zielinska, M.; Atac, A.; Barrientos, D.; Birkenbach, B.; Boston, A. J.; Cederwall, B.; Charles, L.; Collado, J.; Cullen, D. M.; Desesquelles, P.; Domingo-Pardo, C.; Dudouet, J.; Eberth, J.; Gonzalez, V.; Goupil, J.; Harkness-Brennan, L. J.; Hess, H.; Judson, D. S.; Jungclaus, A.; Korten, W.; Labiche, M.; Lefevre, A.; Menegazzo, R.; Mengoni, D.; Nyberg, J.; Perez-Vidal, R. M.; Podolyak, Zs.; Pullia, A.; Recchia, F.; Reiter, P.; Saillant, F.; Salsac, M. D.; Sanchis, E.; Stezowski, O.; Theisen, Ch.; Valiente-Dobon, J. J.; Holt, J. D.; Menendez, J.; Schwenk, A.; Simonis, J.
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Subject
Language
Abstract
To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2+ state in neutron-rich 20O, tau(2+_2 ) = 150(+80-30) fs, 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 femtoseconds range, by analyzing the Doppler-shifted gamma-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction 18O (7.0 MeV/u) + 181Ta. The requested sensitivity could only be reached owing to the excellent performances of the AGATA gamma-tracking array, 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 gamma 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 lifetimes measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense ISOL-type beams become available.