Observation of J/psi-->3gamma.
We report the first observation of the decay J/psi-->3gamma. The signal has a statistical significance of 6sigma and corresponds to a branching fraction of B(J/psi-->3gamma)=(1.2+/-0.3+/-0.2)x10;{-5}, in which the errors are statistical and systematic, respectively. The measurement uses psi(2S)-->pi;{+}pi;{-}J/psi events acquired with the CLEO-c detector operating at the CESR e;{+}e;{-} collider.
Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
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Adams
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Anderson
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Cummings
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Danko
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Moziak
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Napolitano
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Insler
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Muramatsu
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Skwarnicki
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Lincoln
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Rademacker
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Reed
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Vogel
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Alexander
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