Experimental upper limits for the hadronic transitions $\Upsilon (2S)\to \eta \Upsilon$(1S) and $\Upsilon (2S)\to \pi^0\Upsilon$(1S)
- Lurz, B.
- Antreasyan, D.
- Conforto, G.
- Cooper, S.
- Cowan, R.
- Coyne, D.
- Edwards, C.
- Engler, A.
- Folger, G.
- Fridman, A.
- Gaiser, J.
- Gelphman, D.
- Besset, D.
- Godfrey, G.
- Heimlich, F. H.
- Hofstadter, R.
- Irion, J.
- Jakubowski, Z.
- Keh, S.
- Kilian, H.
- Kirkbride, I.
- Kloiber, T.
- Koch, W.
- Bienlein, J. K.
- König, A. C.
- Königsmann, K.
- Kraemer, R. W.
- Lee, R.
- Leffler, S.
- Lekebusch, R.
- Litke, A. M.
- Lockman, W.
- Lowe, S.
- Marlow, D.
- Bloom, E. D.
- Maschmann, W.
- Matsui, T.
- Messing, F.
- Metzger, W. J.
- Monteleoni, B.
- Nernst, R.
- Niczyporuk, B.
- Nowak, G.
- Peck, C.
- Pelfer, P. G.
- Brock, I.
- Pollock, B.
- Porter, F. C.
- Prindle, D.
- Ratoff, P.
- Renger, B.
- Rippich, C.
- Scheer, M.
- Schmitt, P.
- Schotanus, J.
- Schwarz, A.
- Cabenda, R.
- Sievers, D.
- Skwarnicki, T.
- Strauch, K.
- Strohbusch, U.
- Tompkins, J.
- Trost, H. J.
- Walle, R. T.
- Vogel, H.
- Volland, U.
- Wacker, K.
- Cartacci, A.
- Walk, W.
- Wegener, H.
- Williams, D.
- Zschorsch, P.
- Crystal Ball Collaboration
- Cavalli-Sforza, M.
- Clare, R.
DOIAbstract
Using the Crystal Ball detector at thee+e− storage ring DORIS-II, we have searched for the hadronic transitions Υ(2S)→ηΥ(1S) and Υ(2S)→π0Υ(1S) in exclusive decays where the Υ(1S) decays into ane+e− or aµ+µ- pair and the η and π0 are detected by their decay modes η→γγ, η→γγ and π0→γγ. From the number of observed events we derive, after consideration of possible background sources, upper limits on the branching ratiosB(Υ(2S)→ηΥ(1S))<0.7% andB(Υ(2S)→π0Υ(1S))<0.8% at the 90% confidence level
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