Open Access. Powered by Scholars. Published by Universities.®
![Digital Commons Network](http://assets.bepress.com/20200205/img/dcn/DCsunburst.png)
Elementary Particles and Fields and String Theory Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 1 of 1
Full-Text Articles in Elementary Particles and Fields and String Theory
One More Hard Three-Loop Correction To Parapositronium Energy Levels, Michael I. Eides, Valery A. Shelyuto
One More Hard Three-Loop Correction To Parapositronium Energy Levels, Michael I. Eides, Valery A. Shelyuto
Physics and Astronomy Faculty Publications
A hard three-loop correction to parapositronium energy levels of order mα7 is calculated. This nonlogarithmic contribution is due to the insertions of one-loop photon propagator in the fermion lines in the diagrams with virtual two-photon annihilation. We obtained ΔE = 0.03297(2)(mα7 / π3) for this energy shift.