Large-angle Bhabha Scattering and Luminosity at Daφne

The accurate knowledge of luminosity at ee flavour factories requires the precision calculation of the Bhabha cross section at large scattering angles. In order to achieve a theoretical accuracy at the 0.1% level, the relevant effect of QED radiative corrections is taken into account in the framework of the Parton Shower method, which allows exclusive event generation. On this scheme, a Monte Carlo event generator (BABAYAGA) is developed for data analysis. To test the reliability of the approach, a benchmark calculation, including exact O(α) corrections and higher-order leading logarithmic contributions, is developed as well, implemented in a Monte Carlo integrator (LABSPV) and compared in detail with the BABAYAGA predictions. The effect of initial-state and final-state radiation, O(α) next-to-leading and higher-order leading corrections is investigated and discussed in the presence of realistic event selections. The theoretical precision of BABAYAGA is estimated to be at the 0.5% level.