Zb(10610) and Zb(10650) structures produced by the initial single pion emission in the Y(5S) decays

We propose a unique mechanism called initial single pion emission existing in the (5S) decays, and further study the line shapes of d Gamma(Y(5S -> Y(nS)pi(+) pi(-)))/dm(Y(nS)pi+) (n = 1, 2, 3) and d Gamma(Y(5S -> h(b)(mP)pi(+)pi(-)))/dm(hb(mP)pi+) (m = 1, 2). We find sharp structures around 10 610 MeV and 10 650 MeV in the obtained theoretical line shapes of d Gamma(5S -> Y(nS)pi(+)pi(-))/dm(Y(nS)pi+) and d Gamma(Y(5S -> h(b)(mP)pi(+)pi(-)))/dm(hb(mP)pi+) distributions, which could naturally correspond to the Z(b)(10 610) and Z(b)(10 650) structures newly observed by Belle.