Study of the reactions $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0{\pi }^0\gamma$ and ${\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0\eta \gamma$ at center-of-mass energies from threshold to 4.35 GeV using initial-state radiation

Abstract

We study the processes $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0{\pi }^0\gamma$ and ${\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0\eta \gamma$ in which an energetic photon is radiated from the initial state. The data were collected with the BaBar~ detector at SLAC. About 14\,000 and 4700 events, respectively, are selected from a data sample corresponding to an integrated luminosity of 469~$f{b}^{-1}$. The invariant mass of the hadronic final state defines the effective $e^{+}{e}^{-}$ center-of-mass energy. From the mass spectra, the first precise measurement of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0{\pi }^0$ cross section and the first measurement ever of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0\eta$ cross section are performed. The center-of-mass energies range from threshold to 4.35~GeV. The systematic uncertainty is typically between 10 and 13\%. The contributions from $\omega {\pi }^0{\pi }^0$, $\eta {\pi }^{+}{\pi }^{-}$, and other intermediate states are presented. We observe the $J/\psi$ and $\psi (2S)$ in most of these final states and measure the corresponding branching fractions, many of them for the first time.

24 pages, 37 figures