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Observation of h_c(^1P_1) State of Charmonium

J. L. Rosner·CLEO Collaboration
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Abstract

The h_c(1P1) state of charmonium has been observed in the reaction ψ(2S) -> \pi0 h_c -> (γγ)(γη_c) using 3.08 million ψ(2S) decays recorded in the CLEO detector. Data have been analyzed both for the inclusive reaction, where the decay products of the η_c are not identified, and for exclusive reactions, in which η_c decays are reconstructed in seven hadronic decay channels. We find M(h_c)=3524.4 +/- 0.6 +/- 0.4 MeV which corresponds to a hyperfine splitting ΔM_{hf}(1P) \equiv -M(1P1)=+1.0+/-0.6+/-0.4 MeV, and B(ψ(2S)->\pi0 h_c)xB(h_c->γη_c)=(4. +/-0.8+/-0.7)x10^{-4}.

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J. L. Rosner, CLEO Collaboration. 2005-05-24. Observation of h_c(^1P_1) State of Charmonium. https://doi.org/10.1103/physrevlett.95.102003

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