Neutron-distribution radius from higher moments of nuclear charge distribution

par Rika Danjo (Research Center for Accelerator and Radioisotope Science, Tohoku University, Sendai, Japan)

vendredi 9 oct. 2026, 10:30 → 11:30 Europe/Paris

100/-1-A900 - Auditorium Joliot Curie (IJCLab)

The nuclear charge density distribution, $\rho(r)$, determined by elastic electron scattering, provides essential information on nuclear structure. Its moments, $<r_c^n>=\frac{1}{Z}\int r^n \rho_c(r) d^3r$ (Z:atomic number) are also important observables; in particular, the fourth moment, $<r_c^4>$, has recently attracted attention because of its close relation to the neutron distribution radius [1].

The fourth moment can be obtained either from a detailed determination of $\rho(r)$ or from the Taylor expansion of the form factor, $F(q)$, at low momentum transfer.

For heavy nuclei, however, Coulomb distortion makes the latter approach difficult. We have therefore developed a new method to extract $<r_c^4>$ from $F(q)$ at low momentum transfer while taking Coulomb-distortion effects into account [2] . Based on this new method, we conducted an experiment at the low-energy electron-scattering facility ULQ2 at RARiS, Tohoku University, Japan.

In this talk, I will present this method, the ULQ2 experimental program, and its possible extension to neutron- rich unstable nuclei.

[1] H. Kurasawa and T. Suzuki, “The nth-order moment of the nuclear charge density and contribution from the neutrons”, Prog. Theor. Exp. Phys. 2019, 113D01(2019). 
[2] R.Danjo, T.Suda, and T.Suzuki, “A novel method to determine the 4th moment of the ²⁰⁸Pb charge density from low-momentum-transfer electron scattering”, arXiv:2609.22387v2 [nucl-th].