Confirming the molecular nature of the Zb(10610) and the Zb(10650)

The decays of the Z(b)(10610) and the Z(b)(10650) to Upsilon(nS)pi, h(b)(mP)pi and chi(bJ)(mP)gamma (n = 1, 2, 3, m = 1, 2 and J = 0, 1, 2) are investigated within a nonrelativistic effective field theory. It is argued that, while the decays to Upsilon(nS)pi suffer from potentially large higher order corrections, the P-wave transitions of the Zb states are dominated by a single one-loop diagram and therefore offer the best possibility to confirm the nature of the Z(b) states as molecular states and to further study their properties. We give nontrivial and parameter-free predictions for the ratios of various partial widths of the Z(b) and Z(b)' into final states with h(b)(mP)pi and chi(bJ)(mP)gamma. While such relations appear naturally in the molecular picture for the mentioned transitions, they are not expected to hold for any other scenario. In addition, the branching fractions for the neutral Z(b) states to chi(bJ)gamma are predicted to be of order 10(-4)-10(-3). This provides a fine test of the molecular nature in future high-luminosity experiments. DOI: 10.1103/PhysRevD.87.074006