Nuclear Charge Radii of the Nickel Isotopes $^{58-68,70}$Ni

Understand

Collinear laser spectroscopy is performed on the nickel isotopes $^{58-68,70}$Ni, using a time-resolved photon counting system.

• From the measured isotope shifts, nuclear charge radii $R_c$ are extracted and compared to theoretical results.
• Three ab initio approaches all employ, among others, the chiral interaction NNLO$_{\rm sat}$, which allows an assessment of their accuracy.
• We find agreement with experiment in differential radii $\delta \left\langle r_\mathrm{c}^2 \right\rangle$ for all employed ab initio methods and interactions, while the absolute radii are consistent with data only for NNLO$_{\rm sat}$.