51. Inclusive radiativeJ/ψdecays
- Author
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Besson, D, Pedlar, TK, Cronin-Hennessy, D, Gao, KY, Hietala, J, Kubota, Y, Klein, T, Lang, BW, Poling, R, Scott, AW, Zweber, P, Dobbs, S, Metreveli, Z, Seth, KK, Tomaradze, A, Libby, J, Powell, A, Wilkinson, G, Ecklund, KM, Love, W, Savinov, V, Mendez, H, Ge, JY, Miller, DH, Shipsey, IPJ, Xin, B, Adams, GS, Anderson, M, Cummings, JP, Danko, I, Hu, D, Moziak, B, Napolitano, J, He, Q, Insler, J, Muramatsu, H, Park, CS, Thorndike, EH, Yang, F, Artuso, M, Blusk, S, Khalil, S, Li, J, Mountain, R, Nisar, S, Randrianarivony, K, Sultana, N, Skwarnicki, T, Stone, S, Wang, JC, Zhang, LM, Bonvicini, G, Cinabro, D, Dubrovin, M, Lincoln, A, Naik, P, Rademacker, J, Asner, DM, Edwards, KW, Reed, J, Briere, RA, Ferguson, T, Tatishvili, G, Vogel, H, Watkins, ME, Rosner, JL, Alexander, JP, Cassel, DG, Duboscq, JE, Ehrlich, R, Fields, L, Galik, RS, Gibbons, L, Gray, R, Gray, SW, Hartill, DL, Heltsley, BK, Hertz, D, Hunt, JM, Kandaswamy, J, Kreinick, DL, Kuznetsov, VE, Ledoux, J, Mahlke-Krueger, H, Mohapatra, D, Onyisi, PUE, Patterson, JR, Peterson, D, Riley, D, Ryd, A, Sadoff, AJ, Shi, X, Stroiney, S, Sun, WM, Wilksen, T, Athar, SB, Patel, R, Yelton, J, Rubin, P, Eisenstein, BI, Karliner, I, Mehrabyan, S, Lowrey, N, Selen, M, White, EJ, Wiss, J, Mitchell, RE, Shepherd, MR, and Collaboration, CLEO
- Subjects
Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,Branching fraction ,Electron–positron annihilation ,Gamma ray ,Photon energy ,Two-body problem ,01 natural sciences ,Particle identification ,High Energy Physics - Experiment ,Gluon ,0103 physical sciences ,High Energy Physics::Experiment ,Atomic physics ,Cornell Electron Storage Ring ,010306 general physics - 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/{psi}(1S){yields}{gamma}gg, via the ''tagged'' process: e{sup +}e{sup -}{yields}{psi}(2S); {psi}(2S){yields}J/{psi}{pi}{sup +}{pi}{sup -}; J/{psi}{yields}{gamma}+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 [R{sub {gamma}}=B(gg{gamma})/B(ggg)] to be R{sub {gamma}}=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/{psi}{yields}gg{gamma} is observed to be very similar to that of {upsilon}{yields}gg{gamma}. The R{sub {gamma}} value obtained is roughly consistent with that expected by a simple quark-charge scaling [R{sub {gamma}}{approx}(q{sub c}/q{sub b}){sup 2}] of the value determined at the {upsilon}(1S), but somewhat higher than the value expected from the running of the strong coupling constant.
- Published
- 2008
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