Precision spectroscopy on ⁹Be overcomes limitations from nuclear structure

Area of Science:

• Atomic, Molecular & Optical Physics
• Nuclear Physics
• Quantum Electrodynamics

Background:

• Precision atomic spectroscopy is vital for testing fundamental physics, but limited nuclear magnetic property data hinders progress.
• Experimental data for nuclear magnetic properties, especially for heavier elements, is scarce compared to electric properties.

Purpose of the Study:

• To precisely measure nuclear magnetic properties of beryllium-9 (9Be) using high-precision spectroscopy.
• To test theoretical calculations of atomic properties and quantum electrodynamics (QED) by comparing different charge states of 9Be.
• To establish a benchmark for transferring nuclear magnetic property data across various electronic configurations.

Main Methods:

• High-precision spectroscopy of the 1s hyperfine and Zeeman structure in hydrogen-like 9Be3+ ions confined in Penning traps.
• Comparison of spectroscopic data between different charge states of 9Be (9Be3+ and 9Be+).

Main Results:

• Determined the effective Zemach radius of 9Be with 500 ppm uncertainty.
• Measured the bare nuclear magnetic moment of 9Be with an unprecedented 0.6 ppb uncertainty.
• Enabled testing of multi-electron diamagnetic shielding effects and QED calculations at the parts-per-billion level.

Conclusions:

• The study provides highly accurate nuclear magnetic properties for 9Be, crucial for fundamental physics tests.
• The results validate theoretical models for atomic structure and QED in multi-electron systems.
• This work sets a new standard for precision in nuclear magnetic moment measurements beyond hydrogen.