Observation of the P11 state of charmonium

P. Rubin, C. Cawlfield, B. I. Eisenstein, G. D. Gollin, I. Karliner, D. Kim, N. Lowrey, P. Naik, C. Sedlack, M. Selen, E. J. White, J. Williams, J. Wiss, K. W. Edwards, D. Besson, T. K. Pedlar, D. Cronin-Hennessy, K. Y. Gao, D. T. Gong, J. HietalaY. Kubota, T. Klein, B. W. Lang, S. Z. Li, R. Poling, A. W. Scott, A. Smith, S. Dobbs, Z. Metreveli, K. K. Seth, A. Tomaradze, P. Zweber, J. Ernst, A. H. Mahmood, H. Severini, D. M. Asner, S. A. Dytman, W. Love, 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, I. P.J. Shipsey, G. S. Adams, M. Cravey, J. P. Cummings, I. Danko, J. Napolitano, Q. He, H. Muramatsu, C. S. Park, W. Park, E. H. Thorndike, T. E. Coan, Y. S. Gao, F. Liu, M. Artuso, C. Boulahouache, S. Blusk, J. Butt, O. Dorjkhaidav, J. Li, N. Menaa, R. Mountain, R. Nandakumar, K. Randrianarivony, R. Redjimi, R. Sia, T. Skwarnicki, S. Stone, J. C. Wang, K. Zhang, S. E. Csorna, G. Bonvicini, D. Cinabro, M. Dubrovin, R. A. Briere, G. P. Chen, J. Chen, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, J. L. Rosner, N. E. Adam, J. P. Alexander, K. Berkelman, D. G. Cassel, V. Crede, J. E. Duboscq, K. M. Ecklund, R. Ehrlich, L. Fields, R. S. Galik, L. Gibbons, B. Gittelman, R. Gray, S. W. Gray, D. L. Hartill, B. K. Heltsley, D. Hertz, 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, E. A. Phillips, J. Pivarski, D. Riley, A. Ryd, A. J. Sadoff, H. Schwarthoff, X. Shi, M. R. Shepherd, S. Stroiney, W. M. Sun, D. Urner, T. Wilksen, K. M. Weaver, M. Weinberger, S. B. Athar, P. Avery, L. Breva-Newell, R. Patel, V. Potlia, H. Stoeck, J. Yelton

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The spin-singlet P-wave state of charmonium, hc(1P1), has been observed in the decay ψ(2S)→π0hc followed by hc→γηc. Inclusive and exclusive analyses of the M(hc) spectrum have been performed. Two complementary inclusive analyses select either a range of energies for the photon emitted in hc→γηc or a range of values of M(ηc). These analyses, consistent with one another within statistics, yield M(hc)=[3524.9±0.7(stat)±0.4(sys)]MeV/c2 and a product of the branching ratios Bψ(ψ(2S)→π0hc)×Bh(hc→γηc)= [3.5±1.0(stat)±0.7(sys)]×10-4. When the ηc is reconstructed in seven exclusive decay modes, 17.5±4.5 hc events are seen with an average mass M(hc)=[3523.6±0.9(stat)±0.5(sys)]MeV/c2, and BψBh=[5.3±1.5(stat)±1.0(sys)]×10-4. If combined, the inclusive and exclusive data samples yield an overall mass M(hc)=[3524. 4±0.6(stat)±0.4(sys)]MeV/c2 and product of branching ratios BψBh=[4.0±0.8(stat)±0.7(sys)]×10-4. The hc mass implies a P-wave hyperfine splitting ΔMHF(1P)M(13P)-M(11P1)=[1.0±0.6(stat) ±0.4(sys)]MeV/c2.

Original languageEnglish (US)
Article number092004
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number9
StatePublished - Nov 1 2005

ASJC Scopus subject areas

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


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