Nuclear Structure Effects on Hyperfine Splittings in Ordinary and Muonic Deuterium

Area of Science:

• Atomic physics
• Nuclear physics
• Quantum electrodynamics

Background:

• Precision spectroscopy of hyperfine splitting (HFS) is vital for nuclear structure studies and testing quantum electrodynamics.
• Accurate theoretical predictions of HFS are limited by the complexity of two-photon exchange (TPE) effects.

Purpose of the Study:

• To develop a novel, model-independent formalism for calculating TPE effects on HFS.
• To incorporate nuclear excitations and recoil effects within the TPE calculation.
• To improve the accuracy of theoretical predictions for HFS in light and muonic atoms.

Main Methods:

• Developed a new theoretical formalism to describe TPE effects, including nuclear excitations and recoil.
• Combined the new formalism with pionless effective field theory at next-to-next-to-leading order.
• Applied the method to calculate TPE effects on HFS in deuterium and muonic deuterium.

Main Results:

• Predicted TPE effects on HFS for the 1S state in deuterium as 41.7(4.4) kHz.
• Predicted TPE effects on HFS for the 2S state in muonic deuterium as 0.117(13) meV.
• Results show good agreement with recent experimental measurements, within 1σ and 1.3σ.

Conclusions:

• The developed formalism accurately accounts for nuclear structure effects on HFS.
• The findings underscore the significance of nuclear structure in HFS calculations.
• Emphasizes the need for more precise experimental measurements to further validate theoretical models.