Radiative return at NLO and the measurement of the hadronic cross-section in electron--positron annihilation
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
Published online: 5 April 2002
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.
© Società Italiana di Fisica, Springer-Verlag, 2002