Comparisons of the QED and relativistic parts of the triplet-state energies in the heliumlike sequence

We have made a careful comparison of all available high-precision data for the 1s2s ³{S}₁₋₋$1s2p $³P0,1,2 transition energies for all nuclear charges ranging from helium (Z=2) to uranium (Z=92). Systematic discrepancies appear between theory and experiment for the J=1{→}0 transitions, but not for the J=1{→}1 and J=1{→}2 transitions. Analysis of laser-based high-resolution data (Z=2, 3, and 5), beam-foil spectroscopy data (Z=10--17), and hyperfine-quenched decay data (Z>27) suggests an additional contribution to the ³{P}₀$ energy equal to 2.3 (Z/10${)}⁴$ ${cm}^{{{-}}1}$.