Phys. Rev. D
76,
072001
(2007)
[16 pages]
Study of dipion transitions among Υ(3S), Υ(2S), and Υ(1S) states
D. Cronin-Hennessy et al. CLEO Collaboration
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D. Cronin-Hennessy1, K. Y. Gao1, J. Hietala1, Y. Kubota1, T. Klein1, B. W. Lang1, R. Poling1, A. W. Scott1, A. Smith1, P. Zweber1, S. Dobbs2, Z. Metreveli2, K. K. Seth2, A. Tomaradze2, J. Ernst3, K. M. Ecklund4, H. Severini5, W. Love6, V. Savinov6, A. Lopez7, S. Mehrabyan7, H. Mendez7, J. Ramirez7, G. S. Huang8, D. H. Miller8, V. Pavlunin8, B. Sanghi8, I. P. J. Shipsey8, B. Xin8, G. S. Adams9, M. Anderson9, J. P. Cummings9, I. Danko9, D. Hu9, B. Moziak9, J. Napolitano9, Q. He10, J. Insler10, H. Muramatsu10, C. S. Park10, E. H. Thorndike10, F. Yang10, M. Artuso11, S. Blusk11, S. Khalil11, J. Li11, N. Menaa11, R. Mountain11, S. Nisar11, K. Randrianarivony11, R. Sia11, T. Skwarnicki11, S. Stone11, J. C. Wang11, G. Bonvicini12, D. Cinabro12, M. Dubrovin12, A. Lincoln12, S. P. Pappas13, A. J. Weinstein13, D. M. Asner14, K. W. Edwards14, P. Naik14, R. A. Briere15, T. Ferguson15, G. Tatishvili15, H. Vogel15, M. E. Watkins15, J. L. Rosner16, N. E. Adam17, J. P. Alexander17, D. G. Cassel17, J. E. Duboscq17, R. Ehrlich17, L. Fields17, R. S. Galik17, L. Gibbons17, R. Gray17, S. W. Gray17, D. L. Hartill17, B. K. Heltsley17, D. Hertz17, C. D. Jones17, J. Kandaswamy17, D. L. Kreinick17, V. E. Kuznetsov17, H. Mahlke-Krüger17, D. Mohapatra17, P. U. E. Onyisi17, J. R. Patterson17, D. Peterson17, J. Pivarski17, D. Riley17, A. Ryd17, A. J. Sadoff17, H. Schwarthoff17, X. Shi17, S. Stroiney17, W. M. Sun17, T. Wilksen17, S. B. Athar18, R. Patel18, J. Yelton18, P. Rubin19, C. Cawlfield20, B. I. Eisenstein20, I. Karliner20, D. Kim20, N. Lowrey20, M. Selen20, E. J. White20, J. Wiss20, R. E. Mitchell21, M. R. Shepherd21, D. Besson22, and T. K. Pedlar23 (CLEO Collaboration)
1University of Minnesota, Minneapolis, Minnesota 55455, USA
2Northwestern University, Evanston, Illinois 60208, USA
3State University of New York at Albany, Albany, New York 12222, USA
4State University of New York at Buffalo, Buffalo, New York 14260, USA
5University of Oklahoma, Norman, Oklahoma 73019, USA
6University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
7University of Puerto Rico, Mayaguez, Puerto Rico 00681
8Purdue University, West Lafayette, Indiana 47907, USA
9Rensselaer Polytechnic Institute, Troy, New York 12180, USA
10University of Rochester, Rochester, New York 14627, USA
11Syracuse University, Syracuse, New York 13244, USA
12Wayne State University, Detroit, Michigan 48202, USA
13California Institute of Technology, Pasadena, California 91125, USA
14Carleton University, Ottawa, Ontario, Canada K1S 5B6
15Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
16Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA
17Cornell University, Ithaca, New York 14853, USA
18University of Florida, Gainesville, Florida 32611, USA
19George Mason University, Fairfax, Virginia 22030, USA
20University of Illinois, Urbana-Champaign, Illinois 61801, USA
21Indiana University, Bloomington, Indiana 47405, USA
22University of Kansas, Lawrence, Kansas 66045, USA
23Luther College, Decorah, Iowa 52101, USA
Received 15 June 2007; published 4 October 2007
We present measurements of decay matrix elements for hadronic transitions of the form Υ(nS)→Υ(mS)ππ, where (n,m)=(3,1),(2,1),(3,2). We reconstruct charged and neutral pion modes with the final state Upsilon decaying to either μ+μ- or e+e-. Dalitz plot distributions for the 12 decay modes are fit individually as well as jointly assuming isospin symmetry, thereby measuring the matrix elements of the decay amplitude. We observe and account for the anomaly previously noted in the dipion invariant mass distribution for the Υ(3S)→Υ(1S)ππ transition and obtain good descriptions of the dynamics of the decay using the most general decay amplitude allowed by partial conservation of the axial-vector current considerations. The fits further indicate that the Υ(2S)→Υ(1S)ππ and Υ(3S)→Υ(2S)ππ transitions also show the presence of terms in the decay amplitude that were previously ignored, although at a relatively suppressed level.
© 2007 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevD.76.072001
DOI:
10.1103/PhysRevD.76.072001
PACS:
13.20.Gd, 13.25.Gv, 14.40.Gx
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