Hadronic production by ee collisions at the energy 990 MeV with the Orsay storage ring

Data were taken at the energy 2E = 990 MeV to search for multibody events, with the same large solid angle detector which has been used for the measurement of the , ω andφ production by e⁺e^? annilations. Assuming a π⁺π^?π⁰π⁰ production by the quasi two-body process e⁺e^? → → ωπ⁰ we give the correspondi ng cross section σ(e⁺e^? → π⁺π^?π⁰π⁰) = (1.1 ± 0.5) 10^?32 cm². Since no events with 3 and 4 charged pions have been observed σ(e⁺e^? → π⁺π^?π⁰π^?) 1.5 × 10^?33 cm².