Fig. 3. Experimental sensitivity to theoretical contributions.

a–c, Theoretical contributions (from ref. ¹²) to the 1s_1/22p_3/2 J = 2 → 1s_1/22s_1/2 J = 1 intrashell transition energy in He-like uranium (a), to He-like and Li-like uranium transition energy difference (b) and to Be-like and Li-like U transition energy difference (c) in comparison with our experimental precision. For (b) and (c), the blue bar includes non-radiative QED contributions. Some of the corresponding Feynman diagrams are also represented (see also Extended Data Tables 2 and 3). 1e and 2e stand for one-electron and two-electron contributions, respectively.