We present the first measurement of Υ(4S) decays to π+π-Υ(1S) and π+π-Υ(2S) based on a sample of 230×10^6Υ(4S) mesons collected with the BABAR detector. We measure the product branching fractions B(Υ(4S)→π+π-Υ(1S))×B(Υ(1S)→μ+μ-)=(2.23±0.25stat±0.27syst)×10-6 and B(Υ(4S)→π+π-Υ(2S))×B(Υ(2S)→μ+μ-)=(1.69±0.26stat±0.20syst)×10-6, from which we derive the partial widths Γ(Υ(4S)→π+π-Υ(1S))=(1.8±0.4) keV and Γ(Υ(4S)→π+π-Υ(2S))=(2.7±0.8) keV.
Observation of Υ(4S) Decays to π+π-Υ(1S) and π+π-Υ(2S)
SIMI, GABRIELE;GAZ A;MARGONI, MARTINO;SIMONETTO, FRANCO;STROILI, ROBERTO;VOCI, CESARE;
2006
Abstract
We present the first measurement of Υ(4S) decays to π+π-Υ(1S) and π+π-Υ(2S) based on a sample of 230×10^6Υ(4S) mesons collected with the BABAR detector. We measure the product branching fractions B(Υ(4S)→π+π-Υ(1S))×B(Υ(1S)→μ+μ-)=(2.23±0.25stat±0.27syst)×10-6 and B(Υ(4S)→π+π-Υ(2S))×B(Υ(2S)→μ+μ-)=(1.69±0.26stat±0.20syst)×10-6, from which we derive the partial widths Γ(Υ(4S)→π+π-Υ(1S))=(1.8±0.4) keV and Γ(Υ(4S)→π+π-Υ(2S))=(2.7±0.8) keV.File in questo prodotto:
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