Exotic molecular states in the decays of vector bottomonia

• Published in: EPJ Web of Conferences Vol. 212; p. 2002
• Main Authors: Baru, V., Epelbaum, E., Filin, A. A., Hanhart, C., Nefediev, A. V., Wang, Q.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Les Ulis EDP Sciences 2019
• Subjects: Channels; Decay; Interaction parameters; Mathematical analysis; Pions; Quantum numbers
• ISSN: 2100-014X; 2101-6275; 2100-014X
• DOI: 10.1051/epjconf/201921202002

The most recent experimental data for the decays of the vector bottomonium γ(10860) proceeding through the formation of the states Z b (10610) and Z b (10650) are analysed simultaneously using solutions of the Lippmann-Schwinger equations which respect constraints from unitarity and analyticity. The interaction potential in the open-bottom channels $ {B^{(*)}}{\bar B^*} $ contains short-range interactions as well as the one-pion exchange; both types of the interaction are taken into account fully nonperturbatively. This way, all parameters of the interaction are fixed directly from the data and the pole positions for the Z b ’s are determined as a prediction. In particular, both Z b states are found to be described by resonance poles located on the unphysical Riemann sheets in the vicinity of the corresponding thresholds. The heavy quark spin symmetry (HQSS) is employed to predict, in a parameter-free way, the pole positions and the line shapes in the elastic and inelastic channels for the Z b s’ spin partner states W bJ with the quantum numbers J ++ ( J = 0, 1, 2). Such spin partners can be produced in radiative decays of the vector bottomonium Υ(10860) and are expected to be detected in the Belle-II experiment.