Charged bottomoniumlike states Zb(10610) and Zb(10650) and the Y(5S) → Y(2S)π+π- decay

Inspired by the newly observed two charged bottomoniumlike states, we consider the possible contribution from the intermediate Z(b)(10610) and Z(b)(10650) states to the Y(5S) -> Y(2S)pi(+)pi(-) decay process, which naturally explains Belle's previous observation of the anomalous Y(2S)pi(+)pi(-) production near the peak of Y(5S) at root s = 10: 87 GeV [K. F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008)]. The resulting d Gamma(Y(5S) -> Y(2S)pi(+)pi(-))/dm(pi+pi-) and d Gamma(Y(5S) -> Y(2S)pi(+)pi(-))/dcos theta distributions agree with Belle's measurement after inclusion of these Z(b) states. This formalism also reproduces the Belle observation of the double-peak structure and its reflection in the Y(2S)pi(+) invariant mass spectrum of the Y(5S) -> Y(2S)pi(+)pi(-) decay.