Hadronic final states in e+e− annihilation at BaBar

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We present recent results of studies of hadronic final states produced in e++e− annihilation at the BaBar experiment at the PEP-II asymmetric-energy storage rings.We study the processes e+e− → K+K− π0π0 γ, K+ K− π0π0 γ, and K+ K− K+ K− γ, where the photon is radiated from the initial state. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from e+ e− → ϕ(1020)fo(980). In the charmonium region, we observe the J/ψ in all three final states and several intermediate states, as well as the ψ(2S) in some modes, and measure the corresponding branching fractions.We describe the preliminary measurement of the hadronic cross section σ(e+e− → π+π− π0π0) performed via Initial State Radiation in the mass range from 0.95 GeV to 4.5 GeV. We study the s dependence with small point-to-point uncertainties and the internal structure of the π+ π− π0 π0 channel.We report the first observation of e+e− annihilation 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, at energies near s√ = 10.58 GeV. The distributions of cosθ*, where θ* is the center-of-mass polar angle of the ϕson or the forward ρ meson, suggest production by two-virtual-photon annihilation.We present a preliminary study e+e−→ CC events at s√ ≈10.6 GeV containing both a Ac+ baryon and a Ac− antibaryon. We find roughly 4.2 times the number of events expected if the leading charmed hadron types are uncorrelated. These events have a 2-jet topology, but contain very few additional baryons, indicating a previously unobserved type of e+ e− → qq event in which the primary q and q are contained in a correlated baryon and antibaryon and there are multiple intermediate mesons.