Final state radiation and a possibility to test a pion-photon interaction model near two-pion threshold

Abstract

Final state radiation in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ is considered for the cuts used in the analysis of KLOE data at large angles. By means of a Monte Carlo event generator FEVA, effects of non-pointlike behaviour of pions are estimated in the framework of Resonance Perturbation Theory. An additional complication related with the $\varphi$ meson intermediate state is taken into account and the corresponding contributions (the direct decay $\varphi \to {\pi }^{+}{\pi }^{-}\gamma$ and the double resonance decay $\varphi \to {\rho }^{\pm }{\pi }^{\mp }\to {\pi }^{+}{\pi }^{-}\gamma$) are added to FEVA. A method to test effects of non-pointlike behaviour of pions in a model-independent way is proposed.

16 pages, 6 figures

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Cited by in corpus (7)

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• FASTERD: a Monte Carlo event generator for the study of final state radiation in the process $e^{+}{e}^{-}\to \pi \pi \gamma$ at DA$\Phi$NE
• From Hadronic Cross Section to the measurement of the Vacuum Polarization at KLOE: a fascinating endeavour
• Asymmetry observables in e+ e- --> pi+ pi- gamma in the phi region within a chiral unitary approach
• Charge asymmetries in e+e- -> pi+ pi- gamma at the phi resonance
• Structure-dependent radiative corrections to $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma$ in the GVMD approach