All-optical Differential Radii in Zinc

TL;DR

This paper presents high-precision calculations of isotope shift factors in Zn II, enabling more reliable, model-independent measurements of nuclear radii from optical data, which can surpass muonic X-ray methods in accuracy.

Contribution

It introduces a method combining atomic calculations and optical isotope shift data to extract nuclear radii with reduced model dependency, improving nuclear size measurements.

Findings

Differential radii agree with muonic X-ray data for some isotopes but show deviations for deformed nuclei.

Optical isotope shift measurements can provide more reliable nuclear radii than muonic X-ray methods when atomic calculations are accurate.

Deformation effects in Zn nuclei influence the interpretation of isotope shift data, highlighting nuclear structure impacts.

Abstract

We conduct high-accuracy calculations of isotope shift (IS) factors of the states involving the $D_1$ and $D_2$ lines in Zn II. Together with a global fit to the available optical IS data, we extract nuclear-model-independent, precise differential radii for a long chain of Zn isotopes. These radii are compared with the ones inferred from muonic X-ray measurements. Some deviations are found, which we ascribe to the deformed nature of Zn nuclei that introduces nuclear-model dependency into radii extractions from muonic atoms. We arrive at the conclusion that in cases where the many-body atomic calculations of IS factors are well-established, optical determinations of differential radii are more reliable than those extracted from the muonic X-ray measurements, opening the door to improved determination of nuclear radii across the nuclear chart.