Eur. Phys. J. C 24, 71-82 (2002)
https://doi.org/10.1007/s100520200912

Radiative return at NLO and the measurement of the hadronic cross-section in electron--positron annihilation

¹ TH-Division, CERN, 1211 Geneva 23, Switzerland
² Institute of Physics, University of Silesia, 40007 Katowice, Poland
³ Institute of Advanced Study, University of Bologna, 40138 Bologna, Italy
⁴ Institut für Theoretische Teilchenphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany

Received: 14 December 2001
Published online: 5 April 2002

Abstract

Electron--positron annihilation into hadrons plus an energetic photon from initial state radiation allows the hadronic cross-section to be measured over a wide range of energies. The full next-to-leading order QED corrections for the cross-section for e⁺e^- annihilation into a real tagged photon and a virtual photon converting into hadrons are calculated where the tagged photon is radiated off the initial electron or positron. This includes virtual and soft photon corrections to the process e⁺e^- → γ + γ^* and the emission of two real hard photons: e⁺e^- → γ + γ + γ^*. A Monte Carlo generator has been constructed, which incorporates these corrections and simulates the production of two charged pions or muons plus one or two photons. Predictions are presented for centre-of-mass energies between 1 and 10 GeV, corresponding to the energies of DAΦNE, CLEO-C and B-meson factories.