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 — preprints:1997:ttp97-07 [2016/03/15 20:39] (current) Line 1: Line 1: + ====== TTP97-07 Eight-component two-fermion equations ====== + + + An eight-component formalism is proposed for the relativistic two-fermion + problem. In QED, it + extends the applicability of the Dirac equation with hyperfine interaction to + the positronium case. + The use of exact relativistic + two-body kinematics entails a CP-invariant spectrum which is symmetric in + the total cms energy. It + allows the extension of recent $\alpha^6$ recoil corrections to the positronium + case, and + implies new recoil corrections to + the fine and hyperfine structures and to the Bethe logarithm. + + |**R. H\"ackl, V. Hund and H. Pilkuhn**  | + |** Phys. Rev. A57 3268 1998  **  | + | {{preprints:1997:ttp97-07.pdf|PDF}} {{preprints:1997:ttp97-07.ps|PostScript}}   | + | |