Branching ratio and mass spectrum of the decay $\Upsilon^′$$ \to $$\Upsilon$$\pi^+$$\pi^−$
- Albrecht, H.
- Drews, G.
- Gräwe, B.
- Hofmann, W.
- Markees, A.
- Matthiesen, U.
- Spengler, J.
- Wegener, D.
- Heller, R.
- Schubert, K. R.
- Stiewe, J.
- Waldi, R.
- Hasemann, H.
- Weseler, S.
- Edwards, K.
- Frisken, W. R.
- Fukunaga, Ch.
- Goddard, M.
- Kim, P.
- Orr, R. S.
- Patel, P. M.
- Prentice, J. D.
- Seywerd, H.
- Philipp, A.
- Yoon, T.-S.
- Ammar, R.
- Coppage, D.
- Davis, R.
- Kwak, N.
- Böckmann, P.
- Jönsson, L.
- Oku, Y.
- Arefiev, A.
- Danilov, M.
- Schmidt-Parzefall, W.
- Lubimov, V.
- Matveev, V.
- Nagovitsin, V.
- Semenov, Yu.
- Shevchenco, V.
- Soloshenko, V.
- Sopov, V.
- Tchernyshev, V.
- Tichomirov, I.
- Tchistilin, V.
- Schröder, H.
- Zaitsev, Yu.
- Childers, R.
- Darden, C. W.
- Gennow, H.
- ARGUS Collaboration
- Schulz, H. D.
- Selonke, F.
- Wurth, R.
- Drescher, A.
DOIAbstract
The reaction e + e − → ϒ ′ → ϒπ + π − , with ϒ → anything, has been measured using the ARGUS detector at DORIS . We obtain a mass difference M ( ϒ ′) − M ( ϒ ) = (562 ± 3) MeV and a decay branching ratio BR( ϒ ′→ ϒπ + π − )=(17.9±0.9±2.1)%. The invariant mass spectrum of the π + π − system differs from phase space, but is well described by a matrix element of the form ( M ππ 2 − λM π 2 ) with λ =2.6±0.5. We also report preliminary results on the exclusive decay ϒ′ → ϒπ + π − , with ϒ → e + e − , and obtain BR( ϒ → e + e − ) = (2.8 ± 0.4 ± 04±0.3)%
Add to ORKG