Document Type

Article

Publication Date

2026

DOI

10.1016/j.physletb.2026.140962

Publication Title

Physics Letters B

Volume

882

Pages

140962 (6 pp.)

Abstract

Modern atomic spectroscopy has reached a level of precision at which nuclear-structure effects can no longer be neglected and must be quantified reliably. In particular, hyperfine splittings depend on the Zemach radius, which encodes the convolution of the nuclear charge and magnetization distributions. The third electric Zemach moment provides a related finite-size measure and enters the elastic two-photon-exchange contribution to the Lamb shift in muonic atoms. Here, we compute Zemach radii and other electromagnetic moments for light nuclei using quantum Monte Carlo techniques within modern ab initio nuclear theory. Using Norfolk two- and three-body interactions derived within chiral effective field theory, we assess the model dependence and study the role of two-body currents. For ⁶Li, we obtain a Zemach radius larger than that extracted from atomic measurements, consistent with recent calculations, confirming that the discrepancy is not an artifact of the nuclear model. For ⁹Be, our results agree with experiment; the discrepancy of previous phenomenological evaluations is traced to a model-dependent input for the magnetic radius.

Rights

© 2026 The Authors.

This is an open access article under the Creative Commons Attribution 4.0 International (CC BY 4.0) License.

Data Availability

Article states: "Data will be made available on request."

Original Publication Citation

King, G. B., Bacca, S., Chambers-Wall, G., Gnech, A., Pastore, S., Piarulli, M., & Wiringa, R. B. (2026). Quantum Monte Carlo calculations of Zemach moments in A ≤ 9 nuclei. Physics Letters B, 882, Article 140962. https://doi.org/10.1016/j.physletb.2026.140962

ORCID

0000-0002-2077-3866 (Gnech)

Additional Files
1-s2.0-S0370269326008129-mmc1.pdf (66 kB)
Appendix A. Supplementary materials
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