Measurement of the two-loop lamb shift in lithiumlike U89+

Area of Science:

• Atomic Physics
• Quantum Electrodynamics (QED)
• Spectroscopy of Highly Charged Ions

Background:

• Accurate theoretical predictions of atomic properties are crucial for testing fundamental physics.
• Highly charged ions provide extreme conditions to probe QED effects beyond the reach of lighter elements.
• Previous measurements of transitions in heavy, highly charged ions lacked the precision to challenge theoretical calculations.

Purpose of the Study:

• To precisely measure the 2s(1/2)-2p(1/2) transitions in Uranium ions (U88+ and U89+).
• To establish a new experimental benchmark for testing the total QED contribution to transition energies in heavy ions.
• To infer Lamb shift values from experimental transition energies for further theoretical validation.

Main Methods:

• Utilizing the SuperEBIT (Super-Electron Beam Ion Trap) for high-precision spectroscopy.
• Measuring the 2s(1/2)-2p(1/2) transition energies in Lithium-like Uranium (U89+) and its neighboring charge states.
• Employing advanced data analysis to achieve high statistical and systematic accuracy.

Main Results:

• The 2s(1/2)-2p(1/2) transition in Li-like U89+ was measured to be 280.645 ± 0.015 eV.
• This measurement improves precision by nearly an order of magnitude compared to previous data.
• A fractional accuracy of 3.6 x 10(-4) was achieved, setting a new benchmark for QED tests.

Conclusions:

• The experimental results provide stringent tests for theoretical calculations of QED contributions in heavy, highly charged ions.
• An inferred value for the 2s two-loop Lamb shift in U89+ was determined to be -0.23 eV.
• An estimated value for the 1s two-loop Lamb shift in U91+ was derived, offering insights into relativistic and QED effects.