Study of the process e+e-→π+π-γ with the CMD-3 detector at the e+e- collider VEPP-2000

Existing Monte-Carlo generators with radiative corrections to the e+ e- →π+ π - process are usually developed under the assumption that pions can be treated as pointlike particles. We study the e+ e- →π+ π- γ process with final-state radiation and test this assumption using simulated events from the MCGPJ generator based on the scalar QED hypothesis. In order to increase a fraction of events with FSR, the analysis was performed in the energy region to the left from the ρ -meson peak (660÷785 MeV) that is based on the integrated luminosity of about 8.4 pb-1 . The experimental data for the photon energy spectrum agree with the simulation results at 1% level.