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arXiv · 2508.18776

Improved nuclear-structure corrections to the hyperfine splitting of electronic and muonic deuterium

Jose Bonilla·Thomas R. Richardson·Sonia Bacca·Chen Ji·Lucas Platter
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Abstract

We calculate the nuclear-structure correction to the hyperfine splitting in both electronic and muonic deuterium using interactions from chiral effective field theory. We explore the sensitivity to different parameterizations of the nucleon-nucleon force, study the convergence pattern in the order-by-order chiral expansion, and estimate remaining uncertainties. Our results are consistent with earlier calculations from pionless effective field theory, offering new insights for a robust uncertainty quantification. Thanks to the order-of-magnitude reduction in uncertainty achieved with chiral effective field theory, the two-photon exchange contribution in electronic deuterium agrees with experimental extractions within $0.7\sigma$, in contrast to the $2.7\sigma$ discrepancy observed in muonic deuterium. This study lays the groundwork for extending TPE calculations to HFS in heavier atomic systems.

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Jose Bonilla, Thomas R. Richardson, Sonia Bacca, Chen Ji, Lucas Platter. 2025-08-26. Improved nuclear-structure corrections to the hyperfine splitting of electronic and muonic deuterium. https://arxiv.org/abs/2508.18776

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