FINAL-STATE RADIATION AND THE POSSIBILITY TO TEST A PION-PHOTON INTERACTION MODEL NEAR THE TWO-PION THRESHOLD
Pancheri G., Shekhovtsova O., Venanzoni G.

Received: June 26, 2007

PACS: 13.25.Jx, 12.39.Fe, 13.40.Gp

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Final-state radiation in the process e⁺e^-→π⁺π^- is considered for the cuts used in the analysis of KLOE data at large angles. By means of the Monte Carlo event generator FEVA, effects of non-point-like behavior of pions are estimated in the framework of the resonance perturbation theory. An additional complication related to the φ-meson intermediate state is taken into account and the corresponding contributions (the direct decay φ→π⁺π^-γ and the double resonance decay ) are added to FEVA. A method to test effects of non-point-like behavior of pions in a model-independent way is proposed.