Line shapes in Υ(5S) → B(*)(B)over-bar(*)π with Z(10610) and Z(10650) using effective field theory

The Belle Collaboration recently discovered two resonances, Z(b)(10610) and Z(b)(10650)-denoted Z(b) and Z(b)'-in the decays Upsilon(5S) -> Upsilon(nS)pi(+)pi(-) for n = 1, 2, or 3, and Upsilon(5S) -> h(b)(mP)pi(+)pi(-) for m = 1 or 2. These resonances lie very close to the B*(B) over bar and B*(B) over bar* thresholds, respectively. A recent Belle analysis of the three-body decays Upsilon(5S) -> inverted right perpendicularB(()*())(B) over bar (()*())inverted left perpendicular(-/+)pi(+/-) gives further evidence for the existence of these states. In this paper we analyze this decay using an effective theory of B mesons interacting via strong short-range interactions. Some parameters in this theory are constrained using existing data on Upsilon(5S) -> B-(*())(B) over bar (()*()) decays, which requires the inclusion of heavy quark spin symmetry violating operators. We then calculate the differential distribution for Upsilon(5S) -> B-(*())(B) over bar (()*())pi as a function of the invariant mass of the B-(*())(B) over bar (()*()) pair, obtaining qualitative agreement with experimental data. We also calculate angular distributions in the decay Upsilon(5S) -> Z(b)((l))pi which are sensitive to the molecular character of the Z(b)((l)).