On the squared spin-orbit correction to the positronium fine-structure splitting

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153254In the recent paper by Zhang the order $α^4 R_{\infty}$ corrections to the positronium P levels were reconsidered. Those calculations confirm our corresponding results, except for the contribution due to the squared spin-orbit interaction. We present here a new derivation of our previous result for this last correction, this derivation being to our opinion both simple and convincing.3 pages, LatexAtomic PhysicsOn the squared spin-orbit correction to the positronium fine-structure splittingtext