Observation of {upsilon}(4S) Decays to {pi}{sup +}{pi}{sup -}{upsilon}(1S) and {pi}{sup +}{pi}{sup -}{upsilon}(2S)
- Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux (France)
- Facultat de Fisica, Departament ECM, Universitat de Barcelona, E-08028 Barcelona (Spain)
- Dipartimento di Fisica and INFN, Universita di Bari, I-70126 Bari (Italy)
- Institute of High Energy Physics, Beijing 100039 (China)
- Institute of Physics, University of Bergen, N-5007 Bergen (Norway)
We present the first measurement of {upsilon}(4S) decays to {pi}{sup +}{pi}{sup -}{upsilon}(1S) and {pi}{sup +}{pi}{sup -}{upsilon}(2S) based on a sample of 230x10{sup 6}{upsilon}(4S) mesons collected with the BABAR detector. We measure the product branching fractions B({upsilon}(4S){yields}{pi}{sup +}{pi}{sup -}{upsilon}(1S))xB({upsilon}(1S){yields}{mu}{sup +}{mu}{sup -})= =(2.23{+-}0.25{sub stat}{+-}0.27{sub syst})x10{sup -6} and B({upsilon}(4S){yields}{pi}{sup +}{pi}{sup -}{upsilon}(2S))xB({upsilon}(2S){yields}{mu}{sup +}{mu}{sup -})= =(1.69{+-}0.26{sub stat}{+-}0.20{sub syst})x10{sup -6}, from which we derive the partial widths {gamma}({upsilon}(4S){yields}{pi}{sup +}{pi}{sup -}{upsilon}(1S))=(1.8{+-}0.4) keV and {gamma}({upsilon}(4S){yields}{pi}{sup +}{pi}{sup -}{upsilon}(2S))=(2.7{+-}0.8) keV.
- OSTI ID:
- 20775276
- Journal Information:
- Physical Review Letters, Vol. 96, Issue 23; Other Information: DOI: 10.1103/PhysRevLett.96.232001; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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