Phys. Rev. D
76,
072003
(2007)
[9 pages]
Search for radiative decays of Υ(1S) into η and η′
S. B. Athar et al. CLEO Collaboration
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S. B. Athar1, R. Patel1, V. Potlia1, H. Stoeck1, J. Yelton1, P. Rubin2, C. Cawlfield3, B. I. Eisenstein3, I. Karliner3, D. Kim3, N. Lowrey3, P. Naik3, C. Sedlack3, M. Selen3, E. J. White3, J. Wiss3, M. R. Shepherd4, D. Besson5, T. K. Pedlar6, D. Cronin-Hennessy7, K. Y. Gao7, D. T. Gong7, J. Hietala7, Y. Kubota7, T. Klein7, B. W. Lang7, R. Poling7, A. W. Scott7, A. Smith7, S. Dobbs8, Z. Metreveli8, K. K. Seth8, A. Tomaradze8, P. Zweber8, J. Ernst9, H. Severini10, S. A. Dytman11, W. Love11, V. Savinov11, O. Aquines12, Z. Li12, A. Lopez12, S. Mehrabyan12, H. Mendez12, J. Ramirez12, G. S. Huang13, D. H. Miller13, V. Pavlunin13, B. Sanghi13, I. P. J. Shipsey13, B. Xin13, G. S. Adams14, M. Anderson14, J. P. Cummings14, I. Danko14, J. Napolitano14, Q. He15, J. Insler15, H. Muramatsu15, C. S. Park15, E. H. Thorndike15, T. E. Coan16, Y. S. Gao16, F. Liu16, M. Artuso17, S. Blusk17, J. Butt17, J. Li17, N. Menaa17, R. Mountain17, S. Nisar17, K. Randrianarivony17, R. Redjimi17, R. Sia17, T. Skwarnicki17, S. Stone17, J. C. Wang17, K. Zhang17, S. E. Csorna18, G. Bonvicini19, D. Cinabro19, M. Dubrovin19, A. Lincoln19, D. M. Asner20, K. W. Edwards20, R. A. Briere21, I. Brock21, J. Chen21, T. Ferguson21, G. Tatishvili21, H. Vogel21, M. E. Watkins21, J. L. Rosner22, N. E. Adam23, J. P. Alexander23, K. Berkelman23, D. G. Cassel23, J. E. Duboscq23, K. M. Ecklund23, R. Ehrlich23, L. Fields23, R. S. Galik23, L. Gibbons23, R. Gray23, S. W. Gray23, D. L. Hartill23, B. K. Heltsley23, D. Hertz23, C. D. Jones23, J. Kandaswamy23, D. L. Kreinick23, V. E. Kuznetsov23, H. Mahlke-Krüger23, T. O. Meyer23, P. U. E. Onyisi23, J. R. Patterson23, D. Peterson23, J. Pivarski23, D. Riley23, A. Ryd23, A. J. Sadoff23, H. Schwarthoff23, X. Shi23, S. Stroiney23, W. M. Sun23, T. Wilksen23, and M. Weinberger23 (CLEO Collaboration)
1University of Florida, Gainesville, Florida 32611, USA
2George Mason University, Fairfax, Virginia 22030, USA
3University of Illinois, Urbana-Champaign, Illinois 61801, USA
4Indiana University, Bloomington, Indiana 47405, USA
5University of Kansas, Lawrence, Kansas 66045, USA
6Luther College, Decorah, Iowa 52101, USA
7University of Minnesota, Minneapolis, Minnesota 55455, USA
8Northwestern University, Evanston, Illinois 60208, USA
9State University of New York at Albany, Albany, New York 12222, USA
10University of Oklahoma, Norman, Oklahoma 73019, USA
11University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
12University of Puerto Rico, Mayaguez, Puerto Rico 00681
13Purdue University, West Lafayette, Indiana 47907, USA
14Rensselaer Polytechnic Institute, Troy, New York 12180, USA
15University of Rochester, Rochester, New York 14627, USA
16Southern Methodist University, Dallas, Texas 75275, USA
17Syracuse University, Syracuse, New York 13244, USA
18Vanderbilt University, Nashville, Tennessee 37235, USA
19Wayne State University, Detroit, Michigan 48202, USA
20Carleton University, Ottawa, Ontario, Canada K1S 5B6
21Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
22Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA
23Cornell University, Ithaca, New York 14853
Received 23 April 2007; published 11 October 2007
We report on a search for the radiative decay of Υ(1S) to the pseudoscalar mesons η and η′ in (21.2±0.2)×106 Υ(1S) decays collected with the CLEO III detector at the Cornell Electron Storage Ring. The η meson was reconstructed in the three modes η→γγ, η→π+π-π0, or η→π0π0π0. The η′ meson was reconstructed in the mode η′→π+π-η with η decaying through any of the above three modes, and also η′→γρ0, where ρ0→π+π-. Five out of the seven submodes are found to have very low backgrounds. In four of them we find no signal candidates and in one [Υ(1S)→γη′, η′→π+π-η, η→π+π-π0] there are two good signal candidates, which is insufficient evidence to claim a signal. The other two submodes (η→γγ and η′→γρ) are background limited, and show no excess of events in their signal regions. We combine the results from different channels and obtain upper limits at the 90% C.L. which are B(Υ(1S)→γη)<1.0×10-6 and B(Υ(1S)→γη′)<1.9×10-6. Our limits are an order of magnitude tighter than the previous ones and below the predictions made by some theoretical models.
© 2007 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevD.76.072003
DOI:
10.1103/PhysRevD.76.072003
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