7–11 Nov 2022
Seville
Europe/Madrid timezone

Deuteron VVCS and two-photon exchange effects in (muonic) deuterium in pionless EFT

Not scheduled
20m
Seville

Seville

Universidad Pablo de Olavide, de Sevilla, Ctra. de Utrera, km. 1 41013, Sevilla
Parallel contribution Electromagnetic and weak interactions

Speaker

Vadim Lensky (JGU Mainz)

Description

We report on our studies of the forward virtual Compton scattering (VVCS) off a deuteron and the two-photon-exchange corrections to the $S$-levels in muonic ($\mu$D) and ordinary (D) deuterium within the pionless effective field theory (EFT). The spin-independent deuteron VVCS amplitudes are evaluated up to next-to-next-to-next-to-leading order (N3LO) for the longitudinal and next-to-leading order (NLO) for the transverse amplitude. The only unknown low-energy constant enters at N3LO in the former, and describes the coupling of a longitudinal photon to the nucleon-nucleon system. It is extracted using the information about the hydrogen-deuterium isotope shift.
Considering the elastic contribution to the two-photon-exchange in $\mu$D, we emphasize the role of the low-virtuality properties of the deuteron, and identify a correlation between the deuteron charge and Friar radii, which can help one to judge how well a form factor parametrisation describes the aforementioned properties. We also quantify the higher-order two-photon-exchange contributions in $\mu$D, generated by the single-nucleon structure and expected to be the most important terms beyond N3LO.
With the respective two-photon-exchange effects evaluated in a unified pionless EFT approach, the resulting extractions of the deuteron charge radius from the $\mu$D Lamb shift, the $2S-1S$ transition in D, and the $2S-1S$ hydrogen-deuterium isotope shift, are in perfect agreement.

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