Self-energy screening effects in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>g</mml:mi></mml:math> factor of Li-like ions
V. A. Yerokhin, Krzysztof Pachucki, Mariusz Puchalski, Christoph H. Keitel, Z. Harman
Abstract
We report an investigation of the self-energy screening effects for the $g$ factor of the ground state of Li-like ions. The leading screening contribution of the relative order $1/Z$ is calculated to all orders in the binding nuclear strength parameter $Z\ensuremath{\alpha}$ (where $Z$ is the nuclear charge number and $\ensuremath{\alpha}$ is the fine-structure constant). We also extend the known results for the $Z\ensuremath{\alpha}$ expansion of the QED screening correction by deriving the leading logarithmic contribution of order ${\ensuremath{\alpha}}^{5}ln\ensuremath{\alpha}$ and obtaining approximate results for the ${\ensuremath{\alpha}}^{5}$ and ${\ensuremath{\alpha}}^{6}$ contributions. The comparison of the two approaches yields a stringent check of consistency of the two calculations and allows us to obtain improved estimations of the higher-order screening effects.