German Rodrigo

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

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

The radiative return at

e^+ e^-

\phi

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

- and

e^+ e^- \rightarrow \gamma+\gamma^*

B

and the emission of two real hard photons:

-factories: small-angle photon emission at next-to-leading order

e^+ e^- \rightarrow \gamma+\gamma+\gamma^*

The radiative return at phi- and B-factories: FSR at next-to-leading order

. 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 DA

Radiative return at \(\Phi\)- and B-factories: FSR for muon pair production at next-to-leading order

\Phi

The Triple collinear limit of one loop QCD amplitudes

NE, CLEO-C and B-meson factories.

The radiative return at small angles: virtual corrections

Abstract. The radiative return offers the unique possibility for a measurement of the cross section of electron-positron annihilation into hadrons over a wide range of energies. The large luminosity of present