International Conference on Precision Physics of Simple Atomic Systems

Theoretical view on the ground-state hyperfine splitting in muonic hydrogen

21 May 2026, 14:30

30m

Festsaal, Theatersaal (ÖAW)

Talk Session 15

Speaker

Franziska Hagelstein (JGU Mainz & PSI)

Description

I reexamine theory predictions of the ground-state hyperfine splitting in muonic hydrogen. A particular focus will be on proton finite-size and polarizability contributions. The common $(Z \alpha)^5$ finite-size contributions are extended up to and including $(Z \alpha)^6$. Their reanalysis based on electron-proton scattering data is presented, discussing limitations
of the scattering data and in the finite-size expansion. Furthermore, radiative corrections to the finite-size contribution from electron vacuum polarization are presented. Evaluations of the $(Z \alpha)^5$ polarizability contribution in a data-driven dispersive framework [1] and a model-independent prediction in baryon chiral perturbation theory [2] are contrasted.

[1] D. Ruth, K. Slifer, J. P. Chen, C. E. Carlson, F. Hagelstein, V. Pascalutsa, A. Deur, S. Kuhn, M. Ripani and X.~Zheng, et al., Phys. Lett. B 859 (2024), 139116.

[2] F. Hagelstein, V. Lensky and V. Pascalutsa, Eur. Phys. J. C 83 (2023) no. 8, 762.