Phys. Rev. Lett.
95,
102003
(2005)
[5 pages]
Observation of the hc(1P1) State of Charmonium
J. L. Rosner et al. CLEO Collaboration
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J. L. Rosner1, N. E. Adam2, J. P. Alexander2, K. Berkelman2, D. G. Cassel2, V. Crede2, J. E. Duboscq2, K. M. Ecklund2, R. Ehrlich2, L. Fields2, R. S. Galik2, L. Gibbons2, B. Gittelman2, R. Gray2, S. W. Gray2, D. L. Hartill2, B. K. Heltsley2, D. Hertz2, C. D. Jones2, J. Kandaswamy2, D. L. Kreinick2, V. E. Kuznetsov2, H. Mahlke-Krüger2, T. O. Meyer2, P. U. E. Onyisi2, J. R. Patterson2, D. Peterson2, E. A. Phillips2, J. Pivarski2, D. Riley2, A. Ryd2, A. J. Sadoff2, H. Schwarthoff2, X. Shi2, M. R. Shepherd2, S. Stroiney2, W. M. Sun2, D. Urner2, T. Wilksen2, K. M. Weaver2, M. Weinberger2, S. B. Athar3, P. Avery3, L. Breva-Newell3, R. Patel3, V. Potlia3, H. Stoeck3, J. Yelton3, P. Rubin4, C. Cawlfield5, B. I. Eisenstein5, G. D. Gollin5, I. Karliner5, D. Kim5, N. Lowrey5, P. Naik5, C. Sedlack5, M. Selen5, E. J. White5, J. Williams5, J. Wiss5, K. W. Edwards6, D. Besson7, T. K. Pedlar8, D. Cronin-Hennessy9, K. Y. Gao9, D. T. Gong9, J. Hietala9, Y. Kubota9, T. Klein9, B. W. Lang9, S. Z. Li9, R. Poling9, A. W. Scott9, A. Smith9, S. Dobbs10, Z. Metreveli10, K. K. Seth10, A. Tomaradze10, P. Zweber10, J. Ernst11, A. H. Mahmood11, H. Severini12, D. M. Asner13, S. A. Dytman13, W. Love13, S. Mehrabyan13, J. A. Mueller13, V. Savinov13, Z. Li14, A. Lopez14, H. Mendez14, J. Ramirez14, G. S. Huang15, D. H. Miller15, V. Pavlunin15, B. Sanghi15, I. P. J. Shipsey15, G. S. Adams16, M. Cravey16, J. P. Cummings16, I. Danko16, J. Napolitano16, Q. He17, H. Muramatsu17, C. S. Park17, W. Park17, E. H. Thorndike17, T. E. Coan18, Y. S. Gao18, F. Liu18, M. Artuso19, C. Boulahouache19, S. Blusk19, J. Butt19, O. Dorjkhaidav19, J. Li19, N. Menaa19, R. Mountain19, R. Nandakumar19, K. Randrianarivony19, R. Redjimi19, R. Sia19, T. Skwarnicki19, S. Stone19, J. C. Wang19, K. Zhang19, S. E. Csorna20, G. Bonvicini21, D. Cinabro21, M. Dubrovin21, R. A. Briere22, G. P. Chen22, J. Chen22, T. Ferguson22, G. Tatishvili22, H. Vogel22, and M. E. Watkins22 (CLEO Collaboration)
1Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA
2Cornell University, Ithaca, New York 14853
3University of Florida, Gainesville, Florida 32611, USA
4George Mason University, Fairfax, Virginia 22030, USA
5University of Illinois, Urbana-Champaign, Illinois 61801, USA
6Carleton University, Ottawa, Ontario, Canada K1S 5B6 and the Institute of Particle Physics, Canada
7University of Kansas, Lawrence, Kansas 66045, USA
8Luther College, Decorah, Iowa 52101, USA
9University of Minnesota, Minneapolis, Minnesota 55455, USA
10Northwestern University, Evanston, Illinois 60208, USA
11State University of New York at Albany, Albany, New York 12222, USA
12University of Oklahoma, Norman, Oklahoma 73019, USA
13University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
14University of Puerto Rico, Mayaguez, Puerto Rico 00681
15Purdue University, West Lafayette, Indiana 47907, USA
16Rensselaer Polytechnic Institute, Troy, New York 12180, USA
17University of Rochester, Rochester, New York 14627, USA
18Southern Methodist University, Dallas, Texas 75275, USA
19Syracuse University, Syracuse, New York 13244, USA
20Vanderbilt University, Nashville, Tennessee 37235, USA
21Wayne State University, Detroit, Michigan 48202, USA
22Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
Received 23 May 2005; published 31 August 2005
The hc(1P1) state of charmonium has been observed in the reaction ψ(2S)→π0hc→(γγ)(γηc) using 3.08×106 ψ(2S) decays recorded in the CLEO detector. Data have been analyzed both for the inclusive reaction, where the decay products of the ηc are not identified, and for exclusive reactions, in which ηc decays are reconstructed in seven hadronic decay channels. We find M(hc)=3524.4±0.6±0.4 MeV which corresponds to a hyperfine splitting ΔMhf(1P)≡⟨M(3PJ)⟩-M(1P1)=+1.0±0.6±0.4 MeV, and B(ψ(2S)→π0hc)×B(hc→γηc)=(4.0±0.8±0.7)×10-4.
© 2005 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.95.102003
DOI:
10.1103/PhysRevLett.95.102003
PACS:
14.40.Gx, 12.38.Qk, 13.25.Gv, 13.66.Bc
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