TTP99-05 m alpha^7 ln(alpha)^2 corrections to positronium energy levels
TTP99-05 m alpha^7 ln(alpha)^2 corrections to positronium energy levels
TTP99-05 m alpha^7 ln(alpha)^2 corrections to positronium energy levels
We present a calculation of the O(m alpha^7 ln(alpha)^2) corrections
to positronium energy levels. The result is used to estimate the
current uncertainty in theoretical predictions of the positronium spectrum.