Eur. Phys. J. A (2007) 31: 458-460
https://doi.org/10.1140/epja/i2006-10220-8

QNP 2006

Tests of the final-state radiation model at DAFNE near π ⁺ π ^- threshold

¹ INFN Laboratori Nazionale di Frascati, 00044, Frascati (RM), Italy
² NSC “Kharkov Institute for Physics and Technology”, Institute for Theoretical Physics, 61108, Kharkov, Ukraine

Received: 8 November 2006
Accepted: 15 November 2006
Published online: 6 March 2007

Abstract

Effects due to the non-pointlike behaviour of pions in the process e ⁺ e ^-→π ⁺ π ^- γ can arise for hard photons in the final state. By means of a Monte Carlo event generator, which also includes the contribution of the direct decay φ→π ⁺ π ^- γ, we estimate these effects in the framework of the resonance perturbation theory. We consider angular cuts used in the KLOE analysis of the pion form factor at threshold. A method to reveal the effects of the non-pointlike behaviour of pions in a model-independent way is proposed.