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, S. Dobbs, Z. Metreveli, K. K. Seth, A. 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

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

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
Volume78
Issue number3
DOIs
StatePublished - Aug 19 2008

ASJC Scopus subject areas

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

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    Besson, D., Pedlar, T. K., Cronin-Hennessy, D., Gao, K. Y., Hietala, J., Kubota, Y., Klein, T., Lang, B. W., Poling, R., Scott, A. W., Zweber, P., Dobbs, S., Metreveli, Z., Seth, K. K., Tomaradze, A., Libby, J., Powell, A., Wilkinson, G., Ecklund, K. M., ... Shepherd, M. R. (2008). Inclusive radiative J/ψ decays. Physical Review D - Particles, Fields, Gravitation and Cosmology, 78(3), [032012]. https://doi.org/10.1103/PhysRevD.78.032012