Amplitude analysis of e+e- => Y(nS)pi+pi- at sqrt(s)=10.865 GeV
hep-ex
/ Authors
A. Garmash, A. Bondar, A. Kuzmin, A. Abdesselam, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, V. Aulchenko, T. Aushev
and 168 more authors
R. Ayad, A. M. Bakich, A. Bala, V. Bhardwaj, A. Bobrov, G. Bonvicini, A. Bozek, M. Bracko, T. E. Browder, D. Cervenkov, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, R. Chistov, K. Cho, V. Chobanova, Y. Choi, D. Cinabro, J. Dalseno, Z. Dolezal, A. Drutskoy, D. Dutta, S. Eidelman
/ Abstract
We report results on studies of the e+e- annihilation into three-body Y(nS)pi+pi- (n=1,2,3) final states including measurements of cross sections and the full amplitude analysis. The cross sections measured at sqrt(s)=10.865 GeV and corrected for the initial state radiation are sigma(e+e-=>Y(1S)pi+pi-)=(2.27+-0.12+-0.14) pb, sigma(e+e-=>Y(2S)pi+pi-)=(4.07+-0.16+-0.45) pb, and sigma(e+e-=>Y(3S)pi+pi-)=(1.46+-0.09+-0.16) pb. Amplitude analysis of the three-body Y(nS)pi+pi- final states strongly favors I^G(J^P)=1^+(1^+) quantum-number assignments for the two bottomonium-like Zb+- states, recently observed in the Y(nS)pi+- and hb(mP)pi+- (m=1,2) decay channels. The results are obtained with a $121.4 1/fb data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider.