# Studies of Inclusive and Exclusive Final States in $e^+e^-$ Annihilations at low Energies Using Initial State Radiation at BaBar

Abstract : We present studies of the exclusive processes $e^+e^- \rightarrow \gamma e^+e^- \rightarrow \gamma \pi^+\pi^-\pi^0$, $\gamma 2(\pi+\pi^-)$, $\gamma \pi^+\pi^-\pi^0\pi^0$, $\gamma 2(\pi+\pi^-)\pi^0$, $\gamma2(\pi^+\pi^-)\pi^0\pi^0$ and $\gamma 3(\pi^+\pi^-)$, where $\gamma$ is a hard radiative photon, as well as inclusive $\e^+\e^- \rightarrow$ hadrons for energies up to 6.5 GeV. The cross sections for the exclusive modes provide important input into the theoretical calculation of the anomalous magnetic moment of the muon, and the inclusive cross section provides similar input into the running of the fine structure constant. We also find a rich substructure in the exclusive modes and extract cross sections for several intermediate channels. We observe the $J/\psi$ and/or $\psi(2S)$ in several of these modes and measure the corresponding branching fractions.
Document type :
Conference papers

http://hal.in2p3.fr/in2p3-00270444
Contributor : Sabine Starita <>
Submitted on : Friday, April 4, 2008 - 5:16:18 PM
Last modification on : Wednesday, September 16, 2020 - 4:20:32 PM

### Identifiers

• HAL Id : in2p3-00270444, version 1

### Citation

W. Wang. Studies of Inclusive and Exclusive Final States in $e^+e^-$ Annihilations at low Energies Using Initial State Radiation at BaBar. XII International Conference on Hadron Spectroscopy (Hadron07), Oct 2007, Frascati, Italy. ⟨in2p3-00270444⟩

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