Three-body universality in the B meson sector
The charged exotic mesons Z_b(10610) and Z'_b(10650) observed by the Belle collaboration in 2011 are very close to the B* Bbar and B* Bbar* thresholds, respectively. This suggests their interpretation as shallow hadronic molecules of B and B* mesons. Using the masses of the Z_b(10610) and Z'_b(10650) as input, we rule out the possibility for universal bound states of three B and B* mesons arising from the Efimov effect based on their spin-isospin structure. As a consequence, we can predict the phase shifts for the scattering of B and B* mesons off the exotic mesons Z_b(10610) and Z'_b(10650) to leading order in a non-relativistic effective field theory with contact interactions based on two-body information alone.
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