Abstract
The logarithmically enhanced contribution to the hyperfine splitting of the positronium ground-state energy levels is calculated in the framework of dimensionally regularized nonrelativistic quantum electrodynamics. The correction is negative and amounts to about 1/3 of the leading logarithmic one. The discrepancy between the experimental measurements and the theoretical prediction is reduced.
- Received 28 August 2000
DOI:https://doi.org/10.1103/PhysRevLett.85.5094
©2000 American Physical Society