New measurements of Y(1S) decays to charmonium final states

R. A. Briere, G. P. Chen, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, N. E. Adam, J. P. Alexander, K. Berkelman, D. G. Cassel, J. E. Duboscq, K. M. Ecklund, R. Ehrlich, L. Fields, R. S. Galik, L. Gibbons, B. Gittelman, R. Gray, S. W. Gray, D. L. HartillB. K. Heltsley, D. Hertz, L. Hsu, C. D. Jones, J. Kandaswamy, D. L. Kreinick, V. E. Kuznetsov, H. Mahlke-Krüger, T. O. Meyer, P. U.E. Onyisi, J. R. Patterson, D. Peterson, J. Pivarski, D. Riley, J. L. Rosner, A. Ryd, A. J. Sadoff, H. Schwarthoff, M. R. Shepherd, W. M. Sun, J. G. Thayer, D. Urner, T. Wilksen, M. Weinberger, S. B. Athar, P. Avery, L. Breva-Newell, R. Patel, V. Potlia, H. Stoeck, J. Yelton, P. Rubin, B. I. Eisenstein, G. D. Gollin, I. Karliner, D. Kim, N. Lowrey, P. Naik, C. Sedlack, M. Selen, J. J. Thaler, J. Williams, J. Wiss, K. W. Edwards, D. Besson, K. Y. Gao, D. T. Gong, Y. Kubota, S. Z. Li, R. Poling, A. W. Scott, A. Smith, C. J. Stepaniak, J. Urheim, Z. Metreveli, K. K. Seth, A. Tomaradze, P. Zweber, J. Ernst, K. Arms, K. K. Gan, H. Severini, P. Skubic, D. M. Asner, S. A. Dytman, S. Mehrabyan, J. A. Mueller, V. Savinov, Z. Li, A. Lopez, H. Mendez, J. Ramirez, G. S. Huang, D. H. Miller, V. Pavlunin, B. Sanghi, E. I. Shibata, I. P.J. Shipsey, G. S. Adams, M. Chasse, J. P. Cummings, I. Danko, J. Napolitano, D. Cronin-Hennessy, C. S. Park, W. Park, J. B. Thayer, E. H. Thorndike, T. E. Coan, Y. S. Gao, F. Liu, R. Stroynowski, M. Artuso, C. Boulahouache, S. Blusk, J. Butt, E. Dambasuren, O. Dorjkhaidav, N. Menaa, R. Mountain, H. Muramatsu, R. Nandakumar, R. Redjimi, R. Sia, T. Skwarnicki, S. Stone, J. C. Wang, K. Zhang, A. H. Mahmood, S. E. Csorna, G. Bonvicini, D. Cinabro, M. Dubrovin, A. Bornheim, E. Lipeles, S. P. Pappas, A. J. Weinstein

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29 Scopus citations


Using data collected by the CLEO III detector at CESR, we report on measurements of Y(1S) decays to charmonium final states. The data sample used for this analysis consists of 21.2 × 10<sup>6</sup> Y(1S) decays, representing about 35 times more data than previous CLEO Y(1S) data samples. We present substantially improved measurements of the branching fraction B(Y(1S) → J/ψ + X) using J/ψ → μ<sup>+</sup> μ<sup>-</sup> and J/ψ → e<sup>+</sup> e<sup>-</sup> decays. The branching fractions for these two modes are averaged, thereby obtaining: B(Y(1S) → J/ψ + X) = (6.4 ± 0.4(stat) ± 0.6(syst)) × 10<sup>-4</sup>. A greatly improved measurement of the J/ø momentum distribution is presented and indicates a spectrum which is much softer than predicted by the color-octet model and somewhat softer than the color-singlet model. First measurements of the J/ψ polarization and production angle are also presented. In addition, we report on the first observation of Y(1S) → ψA(2S) + X and evidence for Y(1S) → χ<sub>cJ</sub> + X. Their branching fractions are measured relative to B(Y(1S) → J/ψ + X) and are found to be {[B(Y(1S) → ψ(2S) + X)]/[B(Y(1S) → J/ψ + X)]} = 0.41 ± 0.11(stat) ± 0.08(syst), {[B(Y(1S) → χ<sub>c1</sub> + X)]/[B(Y(1S) → J/ψ + X)]} = 0.35 ± 0.08(stat) ± 0.06(syst), {[B(Y(1S) → χ<sub>c2</sub> + X)]/[B(Y(1S) → J/ψ + X)]} = 0.52 ± 0.12(stat) ± 0.09(syst), and {[B(Y(1S) → χ<sub>c0</sub> + X)]/[B(Y(1S) → J/ψ + X)]} < 7.4 at 90% confidence level. The resulting feed-down contributions to J/ψ are [24 ± 6(stat) ± 5(syst)]% for ψ(2S), [11 ± 3(stat) ± 2(syst)]% for χ<sub>c1</sub>, [10 ± 2(stat) ± 2(syst)]% for χ<sub>c2</sub>, and <8.2% at 90% confidence level for ψ<sub>c0</sub>. These measurements (apart from χ<sub>c0</sub>) are about a factor of 2 larger than expected based on the coloroctet model.

Original languageEnglish (US)
Article number072001
Pages (from-to)072001-1-072001-18
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number7
StatePublished - Oct 2004

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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