Inclusive radiative J/ψ decays

D. Besson*, T. K. Pedlar, D. Cronin-Hennessy, K. Y. Gao, J. Hietala, Y. Kubota, T. Klein, B. W. Lang, R. Poling, A. W. Scott, P. Zweber, Sean A Dobbs, Z. Metreveli, Kamal K Seth, Amiran Tomaradze, J. Libby, A. Powell, G. Wilkinson, K. M. Ecklund, W. LoveV. Savinov, H. Mendez, J. Y. Ge, D. H. Miller, I. P.J. Shipsey, B. Xin, G. S. Adams, M. Anderson, J. P. Cummings, I. Danko, D. Hu, B. Moziak, J. Napolitano, Q. He, J. Insler, H. Muramatsu, C. S. Park, E. H. Thorndike, F. Yang, M. Artuso, S. Blusk, S. Khalil, J. Li, R. Mountain, S. Nisar, K. Randrianarivony, N. Sultana, T. Skwarnicki, S. Stone, J. C. Wang, L. M. Zhang, G. Bonvicini, D. Cinabro, M. Dubrovin, A. Lincoln, P. Naik, J. Rademacker, D. M. Asner, K. W. Edwards, J. Reed, R. A. Briere, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, J. L. Rosner, J. P. Alexander, D. G. Cassel, J. E. Duboscq, R. Ehrlich, L. Fields, R. S. Galik, L. Gibbons, R. Gray, S. W. Gray, D. L. Hartill, B. K. Heltsley, D. Hertz, J. M. Hunt, J. Kandaswamy, D. L. Kreinick, V. E. Kuznetsov, J. Ledoux, H. Mahlke-Krüger, D. Mohapatra, P. U.E. Onyisi, J. R. Patterson, D. Peterson, D. Riley, A. Ryd, A. J. Sadoff, X. Shi, S. Stroiney, W. M. Sun, T. Wilksen, S. B. Athar, R. Patel, J. Yelton, P. Rubin, B. I. Eisenstein, I. Karliner, S. Mehrabyan, N. Lowrey, M. Selen, E. J. White, J. Wiss, R. E. Mitchell, M. R. Shepherd

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Using data taken with the CLEO-c detector at the Cornell Electron Storage Ring, we have investigated the direct-photon momentum spectrum in the decay J/ψ(1S)→γgg, via the "tagged" process: e+e-→ψ(2S); ψ(2S)→J/ψπ+π-; J/ψ→γ+X. Including contributions from two-body radiative decay processes, we find the ratio of the inclusive direct-photon branching fraction to that of the dominant three-gluon branching fraction [Rγ=B(ggγ)/B(ggg)] to be Rγ=0.137±0.001±0.016±0.004, where the errors shown are statistical, systematic, and the model-dependent uncertainty related to the extrapolation to zero photon energy. The shape of the scaled photon energy spectrum in J/ψ→ggγ is observed to be very similar to that of Υ→ggγ. The Rγ value obtained is roughly consistent with that expected by a simple quark-charge scaling [Rγ∼(qc/qb)2] of the value determined at the Υ(1S), but somewhat higher than the value expected from the running of the strong coupling constant.

Original languageEnglish (US)
Article number032012
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number3
StatePublished - Aug 19 2008

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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