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Observation of Upsilon(4S) decays to pi(+)pi(-)Upsilon(1S) and pi(+)pi(-)Upsilon(2S) |
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| Authors: | Aubert B Barate R Bona M Boutigny D Couderc F Karyotakis Y Lees J P Poireau V Tisserand V Zghiche A Grauges E Palano A Chen J C Qi N D Rong G Wang P Zhu Y S Eigen G Ofte I Stugu B Abrams G S Battaglia M Brown D N Button-Shafer J Cahn R N Charles E Gill M S Groysman Y Jacobsen R G Kadyk J A Kerth L T Kolomensky Yu G Kukartsev G Lynch G Mir L M Oddone P J Orimoto T J Pripstein M Roe N A Ronan M T Wenzel W A Barrett M Ford K E Harrison T J Hart A J Hawkes C M Morgan S E Watson A T Goetzen K Held T Koch H Lewandowski B Pelizaeus M Peters K Schroeder T Steinke M Boyd J T Burke J P Cottingham W N |
| Institution: | Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France. |
| Abstract: | Observation of Upsilon(4S) decays to pi(+)pi(-)C and pi(+)pi(-)Upsilon(2S)We present the first measurement of Upsilon(4S) decays to pi(+)pi(-)Upsilon(1S) based on a sample of 230 x 106(4S) mesons collected with the BABAR detector. We measure the product branching fractions Beta(Upsilon(4S) --> pi(+)pi(-)Upsilon(1S)) x BetaUpsilon(1S) --> mu(+)mu(-) = (2.23 +/- 0.25(stat) +/- 0.27(syst))x 10(-6) and Beta(Upsilon(4S) --> pi(+)pi(-)Upsilon(2S) x Beta(Upsilon(2S) --> mu(+)mu(-))=(1.69 +/-0.26(stat) +/- 0.20(syst)) x 10(-)6, from which we derive the partial widths Gamma(Upsilon(4S) --> pi(+)pi(-)Upsilon(1S))=(1.8 +/-0.4) keV and Gamma(Upsilon(4S) --> pi(+)pi(-)Upsilon(2S))=(2.7 +/- 0.8) keV. |
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