Virtual two-loop corrections to Bhabha scattering

The author has developed methods for the calculation of contributions from six ladder-like diagrams to Bhabha scattering. The leading terms both for separate diagrams and for the sum of the gauge-invariant set of all diagrams have been calculated. The study has been limited to contributions from Feynman diagrams without real photons, and all calculations have been done with s>> |t| >>m2, where s is the center of mass energy squared, t is the square of the transferred four-momentum, and m is the electron mass. For the separate diagrams the results depend upon how λ2 is related to s, |t| and m2, whereas the leading term of the sum of the six diagrams is the same in the cases that have been considered. The methods described should be valuable for calculations of contributions from other Feynman diagrams, in particular QED corrections to Bhabha scattering or pair production at small angles. 23 refs., 5 figs., 5 tabs