Cronin-Hennessy, D. and Gao, K. Y. and Hietala, J. and Kubota, Y. and Klein, T. and Lang, B. W. and Poling, R. and Scott, A. W. and Smith, A. and Zweber, P. and Dobbs, S. and Metreveli, Z. and Seth, K. K. and Tomaradze, A. and Ernst, J. and Ecklund, K. M. and Severini, H. and Love, W. and Savinov, V. and Lopez, A. and Mehrabyan, S. and Mendez, H. and Ramirez, J. and Huang, G. S. and Miller, D. H. and Pavlunin, V. and Sanghi, B. and Shipsey, I. P. J. and Xin, B. and Adams, G. S. and Anderson, M. and Cummings, J. P. and Danko, I. and Hu, D. and Moziak, B. and Napolitano, J. and He, Q. and Insler, J. and Muramatsu, H. and Park, C. S. and Thorndike, E. H. and Yang, F. and Artuso, M. and Blusk, S. and Khalil, S. and Li, J. and Menaa, N. and Mountain, R. and Nisar, S. and Randrianarivony, K. and Sia, R. and Skwarnicki, T. and Stone, S. and Wang, J. C. and Bonvicini, G. and Cinabro, D. and Dubrovin, M. and Lincoln, A. and Pappas, S. P. and Weinstein, A. J. and Asner, D. M. and Edwards, K. W. and Naik, P. and Briere, R. A. and Ferguson, T. and Tatishvili, G. and Vogel, H. and Watkins, M. E. and Rosner, J. L. and Adam, N. E. and Alexander, J. P. and Cassel, D. G. and Duboscq, J. E. and Ehrlich, R. and Fields, L. and Galik, R. S. and Gibbons, L. and Gray, R. and Gray, S. W. and Hartill, D. L. and Heltsley, B. K. and Hertz, D. and Jones, C. D. and Kandaswamy, J. and Kreinick, D. L. and Kuznetsov, V. E. and Mahlke-Krüger, H. and Mohapatra, D. and Onyisi, P. U. E. and Patterson, J. R. and Peterson, D. and Pivarski, J. and Riley, D. and Ryd, A. and Sadoff, A. J. and Schwarthoff, H. and Shi, X. and Stroiney, S. and Sun, W. M. and Wilksen, T. and Athar, S. B. and Patel, R. and Yelton, J. and Rubin, P. and Cawlfield, C. and Eisenstein, B. I. and Karliner, I. and Kim, D. and Lowrey, N. and Selen, M. and White, E. J. and Wiss, J. and Mitchell, R. E. and Shepherd, M. R. and Besson, D. and Pedlar, T. K. (2007) Study of dipion transitions among Υ(3S), Υ(2S), and Υ(1S) states. Physical Review D, 76 (7). Art. No. 072001. ISSN 0556-2821 http://resolver.caltech.edu/CaltechAUTHORS:20100112-082432249
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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.
|Additional Information:||© 2007 The American Physical Society. Received 15 June 2007; published 4 October 2007. We gratefully acknowledge the effort of the CESR staff in providing us with excellent luminosity and running conditions. D. C.-H. and A. R. thank the A. P. Sloan Foundation. This work was supported by the National Science Foundation, the U.S. Department of Energy, and the Natural Sciences and Engineering Research Council of Canada.|
|Classification Code:||PACS numbers: 13.20.Gd, 13.25.Gv, 14.40.Gx.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||12 Jan 2010 23:04|
|Last Modified:||26 Dec 2012 11:41|
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