We study transitions between Υ states with the emission of charged pions using 604.6fb-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The measured product branching fraction is B(Υ(4S)→Υ(1S)π+π-)×B(Υ(1S)→μ+μ-)=(2. 11±0.30(stat)±0.14(sys))×10-6 and the partial decay width is Γ(Υ(4S)→Υ(1S)π+π-)=(1.75±0.25(stat)±0. 24(sys))keV. © 2009 The American Physical Society.
Olivier Schneider, Yiming Li, Mingkui Wang, Chao Wang, Tagir Aushev, Sun Hee Kim, Ke Huang, Donghyun Kim
Clement Helsens, Donal Patrick Hill, Marie Hartmann
Olivier Schneider, Yiming Li, Mingkui Wang, Chao Wang, Tagir Aushev, Sun Hee Kim, Donghyun Kim, Xiao Wang, Lei Li