フロンティア・シミュレーション、物議を醸すカルシウム48の核磁気励起に新たな知見を提供(Frontier simulations provide new insights into calcium-48’s controversial nuclear magnetic excitation)

2024-09-03 オークリッジ国立研究所(ORNL)

＜関連情報＞

• https://www.ornl.gov/news/frontier-simulations-provide-new-insights-calcium-48s-controversial-nuclear-magnetic
• https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.232504

48Caの磁気双極子転移 Magnetic Dipole Transition in 48Ca

B. Acharya, B. S. Hu, S. Bacca, G. Hagen, P. Navrátil, and T. Papenbrock
Physical Review Materials  Published 7 June 2024
DOI:https://doi.org/10.1103/PhysRevLett.132.232504

Abstract

The magnetic dipole transition strength ⁡(⁢1) of ⁴⁸Ca is dominated by a single resonant state at an excitation energy of 10.23 MeV. Experiments disagree about ⁡(⁢1) and this impacts our understanding of spin flips in nuclei. We performed ab initio computations based on chiral effective field theory and found that ⁡(⁢1:  0⁺→1⁺) lies in the range from 7.0 to 10.2  ². This is consistent with a (,) experiment but larger than results from (,′) and (,′) scattering. Two-body currents yield no quenching of the ⁡(⁢1) strength and continuum effects reduce it by about 10%. For a validation of our approach, we computed magnetic moments in ^47,49Ca and performed benchmark calculations in light nuclei.