Energy corrections of order mc2 alpha 6ln alpha in helium.

Abstract

Quantum-electrodynamic corrections of O(${\mathit{mc}}^{2}$${\mathrm{\ensuremath{\alpha}}}^{6}$ln\ensuremath{\alpha}) to the electron-electron interaction in helium are evaluated for several states. The additional energy shift, which is an order of \ensuremath{\alpha} smaller than the leading Araki-Sucher terms, raises the predicted energy of the 1s2s $^{1}$${\mathit{S}}_{0}$ state by 2.49 MHz to -960 332 039.43(18) MHz relative to ${\mathrm{He}}^{+}$(1s). The new value significantly alters the comparison with recent high-precision experiments.