Speaker
Description
In this presentation, I will discuss the results for the $O(\alpha^5)$ effects of the nuclear structure, the two-photon-exchange (TPE) corrections, in the energies of S-levels in muonic ($\mu$D) and ordinary (D) deuterium. They were recently obtained at next-to-next-to-next-to-leading order (N3LO) in the pionless effective field theory (EFT). At this order, there is a single low-energy constant that is fitted to the hydrogen-deuterium isotope shift. This constant generates a correlation between the deuteron charge and Friar radii. This correlation can be used to judge how well a deuteron charge form factor parametrization describes the low-virtuality properties of the deuteron. The pionless EFT evaluation of the TPE corrections in $\mu$D and D allows one to extract the deuteron charge radius $r_d$ from the $\mu$D Lamb shift, the $2S-1S$ transition in D, and the $2S-1S$ hydrogen–deuterium isotope shift in a unified approach, giving values of $r_d$ that are in agreement [1,2]. I will also discuss the role of the TPE corrections generated by the structure of the individual nucleons.
[1] V. Lensky, F. Hagelstein and V. Pascalutsa, Eur. Phys. J. A 58 (2022), 224 [arXiv:2206.14756 [nucl-th]].
[2] V. Lensky, F. Hagelstein and V. Pascalutsa, Phys. Lett. B 835 (2022), 137500 [arXiv:2206.14066 [nucl-th]].
