Observation of e+e- Annihilations into the C=+1 Hadronic Final States rho0 rho0 and phi rho0

The authors report the first observation of e+e- annihilations into states of positive C-parity, namely ρ0ρ0 and φρ0. The two states are observed in the π+π-π+π- and K+K- π+π- final states, respectively, in a data sample of 225 fb-1 collected by the BABAR experiment at the PEP-II e+e- storage rings at energies near √s = 10.58 GeV. The distributions of cos θ*, where θ* is the center-of-mass polar angle of the φ meson or the forward ρ0 meson, suggest production by two-virtual-photon annihilation. They measure cross sections within the range |cos θ*| < 0.8 of σ(e+e- → ρ0 ρ0) = 20.7 ± 0.7(stat) ± 2.7(syst) fb and σ(e+e- → φρ0) = 5.7 ± 0.5(stat) ± 0.8(syst) fb