Precise determination of the 1s Lamb Shift in hydrogen-like lead and gold ions using microcalorimeters

TL;DR

This paper reports the precise measurement of the 1s Lamb Shift in hydrogen-like lead and gold ions using silicon microcalorimeters, providing a critical test of quantum electrodynamics in strong Coulomb fields.

Contribution

It introduces a novel microcalorimeter-based method for detecting hard X-rays, achieving the most accurate Lamb Shift measurements in hydrogen-like lead.

Findings

Lamb Shift in lead: 260 ± 22 eV

Lamb Shift in gold: 208 ± 13 eV

Results agree with theoretical predictions

Abstract

Quantum electrodynamics in very strong Coulomb fields is one scope which has not yet been tested experimentally with suffcient accuracy to really determine whether the perturbative approach is valid. One sensitive test is the determination of the 1s Lamb Shift in highly-charged very heavy ions. The 1s Lamb Shift of hydrogen-like lead (Pb81+) and gold (Au78+) has been determined using the novel detector concept of silicon microcalorimeters for the detection of hard X-rays. The results of (260 +- 22) eV for lead and (208 +- 13) eV for gold are within error bars in good agreement with theoretical predictions. For hydrogen-like lead, this represents the most accurate determination of the 1s Lamb Shift to our knowledge.