Three-body forces in carbon and oxygen nuclei

To test the predictive power of ab initio nuclear structure models, the lifetime of the second 2⁺ state in neutron-rich ²⁰O, τ(2₂⁺)=150(-30,+80)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 femtosecond range by analyzing the Doppler-shifted gamma-transition line shapes of nuclei measured by  AGATA+PARIS+VAMOS setup. The experimental lifetimes agree with predictions of ab initio calculations using  two- and three-nucleon interactions for ²⁰O and ¹⁶C. The present measurement shows the power of observables provided by electromagnetic transitions, determined with high-precision gamma spectroscopy, in assessing the quality of first-principles nuclear structure calculations.

M.Ciemała, (B.Fornal, A.Maj, P.Bednarczyk, N.Cieplicka-Orynczak, J.Grębosz, Ł.W.Iskra, M.Kicinska-Habior, M.Kmiecik, M.Lewitowicz, K.Mazurek, M.Matejska-Minda, P.Napiorkowski, M.Rejmund, B.Wasilewska, M.Zieblinski) et al.

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

Physical Review C 101, 021303(R) (2020)
https://doi.org/10.1103/PhysRevC.101.021303