The $g$ factor of bound electrons as a test for physics beyond the Standard Model

Abstract

The use of high-precision measurements of the g factor of few-electron ions and its isotope shifts is put forward as a probe for physics beyond the Standard Model. The contribution of a hypothetical fifth fundamental force to the g factor is calculated for the ground state of H-like, Li-like and B-like ions, and employed to derive bounds on the parameters of that force. The weighted difference and especially the isotope shift of g factors are used in order to increase the experimental sensitivity to the new physics contribution. It is found that, combining measurements from four different isotopes of H-like, Li-like and B-like calcium ions at currently accessible accuracy levels, experimental results compatible with King planarity would constrain the new physics coupling constant more than one order of magnitude further than the best current atomic data.

Skyrme-type nuclear interaction as a tool for calculating the finite nuclear size correction to atomic energy levels and the bound-electron $g$ factor

“…Such a high accuracy has also been employed for a precise determination of the electron mass [6] and it has been proposed to be used for determination of the fine-structure constant [7][8][9] and even for search of its hypothetical variation [10][11][12][13][14]. Moreover, comparison between the experimental and theoretical results can be used to test theories beyond the Standard Model by setting bounds on parameters of new hypothetical forces [15]. Among various achievements in this field, the most prominent ones include measurements and calculations of the bound-electron g factor in highly charged ions to an extraordinary level of precision [16][17][18][19][20][21].…”