Model-independent determination of nuclear charge radii from Li-like ions

We demonstrate that recent advances in QED theory of Li-like ions [V. A. Yerokhin, , ] enable determinations of absolute nuclear charge radii for heavy elements. By incorporating constraints derived from electron-scattering data, we obtain radii that are independent of the assumed model of the nuclear charge distribution. Our approach is validated for <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mmultiscripts> <a:mi>Pb</a:mi> <a:mprescripts/> <a:none/> <a:mn>208</a:mn> </a:mmultiscripts> </a:math> , a well-studied spherical nucleus, and is then applied to <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:mmultiscripts> <b:mi>Bi</b:mi> <b:mprescripts/> <b:none/> <b:mn>209</b:mn> </b:mmultiscripts> </b:math> , where low-lying nuclear excitations complicate the interpretation of muonic-atom data.