Observation of e(+)e(-) annihilation into the C=+1 hadronic final states rho(0)rho(0) and phi rho(0)

We report the first observation of e(+)e(-) annihilation into states of positive C parity, namely, rho(0)rho(0) and phi rho(0). The two states are observed in the pi(+)pi(-)pi(+)pi(-) and K+K-pi(+)pi(-) final states, respectively, in a data sample of 225 fb(-1) collected by the BABAR experiment at the Positron-Electron Project II e(+)e(-) storage rings at energies near root s=10.58 GeV. The distributions of cos theta(*), where theta(*) is the center-of-mass polar angle of the phi meson or the forward rho(0) meson, suggest production by two-virtual-photon annihilation. We measure cross sections within the range vertical bar cos theta(*)vertical bar < 0.8 of sigma(e(+)e(-)->rho(0)rho(0))=20.7 +/- 0.7(stat)+/- 2.7(syst) fb and sigma(e(+)e(-)->phi rho(0))=5.7 +/- 0.5(stat)+/- 0.8(syst) fb.