QED $m{\alpha }^7$ effects for triplet states of helium-like ions

Abstract

We perform ab initio calculations of the QED effects of order $m{\alpha }^7$ for the $2^{3}S$ and $2^{3}P$ states of He-like ions. The computed effects are combined with previously calculated energies from [V. A. Yerokhin and K. Pachucki, Phys. Rev. A 81, 022507 (2010)], thus improving the theoretical accuracy by an order of magnitude. The obtained theoretical values for the $2^{3}S$-$2^3{P}_{0,2}$ transition energies are in good agreement with available experimental results and with previous calculations performed to all orders in the nuclear binding strength parameter $Z\alpha$. For the ionization energies, however, we find some inconsistency between the $Z\alpha$-expansion and all-order calculations, which might be related to a similar discrepancy between the theoretical and experimental results for the ionization energies of helium [V. Patkóš et al., Phys. Rev. A 103, 042809 (2021)].

References in corpus (4)

• Complete ${\alpha }^{7}m$ Lamb shift of helium triplet states
• QED calculations of energy levels of helium-like ions with $5\le Z\le 30$
• Radiative ${\mathbf{\alpha }}^7\mathbf{m}$ QED contribution to the helium Lamb shift
• Relativistic Bethe logarithm for triplet states of helium-like ions

Cited by in corpus (3)

• Towards Precision Muonic X-Ray Measurements of Charge Radii of Light Nuclei
• Imaging-assisted single-photon Doppler-free laser spectroscopy and the ionization energy of metastable triplet helium
• Collinear Laser Spectroscopy of $2{}^3{S}_1\to 2{}^3{P}_J$ transitions in helium-like ${}^{12}{\mathrm{C}}^{4+}$