Radiative transitions fromΥ(5S)to molecular bottomonium

Abstract

The heavy quark spin symmetry implies that in addition to the recently observed $Z(10610)$ and $Z(10650)$ molecular resonances with ${I}^{G}={1}^{+}$, there should exist two or four molecular bottomonium-like states with ${I}^{G}={1}^{\ensuremath{-}}$. Properties of these $G$-odd states are considered, including their production in the radiative transitions from $\ensuremath{\Upsilon}(5S)$, by applying the same symmetry to the $\ensuremath{\Upsilon}(5S)$ resonance and the transition amplitudes. The considered radiative processes can provide a realistic option for observing the yet hypothetical states.