Radiative return at NLO and the measurement of the hadronic cross-section

Abstract

The measurement of the hadronic cross-section in $e^+ e^-$ annihilation at high luminosity factories using the radiative return method is motivated and discussed. A Monte Carlo generator which simulates the radiative process $e^+ e^- \to \gamma+hadrons$ at the next-to-leading order accuracy is presented. The analysis is then extended to the description of events with hard photons radiated at very small angle.Comment: 12 pages, 6 figures. To appear in Acta Physica Polonica B. Presented at the XXV International Conference on Theoretical Physics ``Particle Physics and Astrophysics in the Standard Model and Beyond'', Ustron, Poland, 9-16 September 200