2018 Impact factor 4.843
Particles and Fields

Eur. Phys. J. C 22, 81-88 (2001)
DOI: 10.1007/s1005201O0784

NLO QED corrections to ISR in e+ e- annihilation and the measurement of $\sigma(e^+ e^- \rightarrow {\mathrm {hadrons}})$ using tagged photons

G. Rodrigo1, A. Gehrmann-De Ridder1, 2, M. Guilleaume1 and J.H. Kühn1

1  Institut für Theoretische Teilchenphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany
2  Theory Division, CERN, 1211 Geneva 23, Switzerland

(Received: 14 June 2001 / Published online: 5 October 2001 - © Springer-Verlag / Società Italiana di Fisica 2001 )

The leptonic tensor for the process $e^+ e^- \rightarrow \gamma+\gamma^*$, which describes the next-to-leading order virtual and soft QED corrections to initial state radiation in e+ e- annihilation with emission of an extra virtual photon decaying into hadrons, is calculated. A Monte Carlo generator for the reaction $e^+ e^- \rightarrow \gamma + \pi^+ \pi^-$ has been set up which includes these corrections. It thus describes configurations where the invariant mass of the hadrons plus photon is very close to s1/2. Predictions for cms energies of 1 to 10 GeV, corresponding to the energies of DAPHNE and B-meson factories, are presented. The possibility for an accurate measurement using tagged photons of $\sigma(e^+ e^- \rightarrow {\mathrm {hadrons}})$ , which plays an important role in the theoretical description of the muon anomalous magnetic moment and the running of the electromagnetic coupling, is discussed.

© Società Italiana di Fisica, Springer-Verlag 2001