TTP03-29 The radiative return at phi- and B-factories: a Status Report

The measurement of the pion form factor and, more generally, of the cross section for electron–positron annihilation into hadrons through the radiative return has become an important task for high luminosity colliders such as the $\Phi$- or $B$-meson factories. For detailed understanding and analysis of this reaction, the construction of a Monte Carlo program, PHOKHARA, has been undertaken. Version 2.0 was based on a next-to-leading order (NLO) treatment of the corrections from initial-state radiation (ISR) and leading order final-state radiation (FSR). The most recent extension of PHOKHARA (version 3.0), which incorporates NLO corrections to FSR and the impact of combined ISR and FSR on selected distributions, is presented.