====== TTP08-26 Two-loop QED hadronic corrections to Bhabha scattering ======
 
 
   <hidden TTP08-26  Two-loop QED hadronic corrections to Bhabha scattering > heoretical predictions for Bhabha scattering at the two-loop level require the inclusion of
 hadronic vacuum polarization in the photon propagator. We present predictions for the contri
 butions from reducible amplitudes which are proportional to the vacuum polarization $\pi(q^2
 )$ and from irreducible ones where the vacuum polarization appears in a loop representing ve
 rtex or box diagrams. The second case can be treated by using dispersion relations with a we
 ight function proportional to the $R$-ratio as measured in electron-positron annihilation in
 to hadrons and kernels that can be calculated perturbatively. We present simple analytical f
 orms for the kernels and, using two convenient parametrizations for the function $R(s)$, num
 erical results for the quantities of interest. As a cross check we evaluate the correspondin
 g corrections resulting from light and heavy lepton loops and we find perfect agreement with
  previous calculations. For the hadronic correction our result are in good agreement with a
 previous evaluation.
 </hidden>
|**Johann H. K&uuml;hn and Sandro Uccirati**  | 
|**  Nucl.Phys.  B806 300-326 2009  **  |
| {{preprints:2008:ttp08-26.pdf|PDF}} {{preprints:2008:ttp08-26.ps|PostScript}} [[http://arxiv.org/abs/0807.1284|arXiv]]   |
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