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arXiv · 1105.5492

An explanation of Belle states Z_b(10610) and Z_b(10650)

D. V. Bugg
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Abstract

Belle report data on Upsilon (5S) -> Upsilon(1S,2S,3S)-piplus-piminus and chi_b(1P,2P)-piplus-piminus; they observe peaks in Upsilon-pi and chi_b-pi consistent with J^P=1^+. They interpret the peaks as molecular states Z_b(10608) and Z_b(10653). Their masses are just above Bbar-B^* and B^*bar-B^* thresholds at 10604.6 and 10650.2 MeV. An explanation in terms of cusps at these thresholds is presented here. The product of the rising phase space for Bbar-B^* and B^*bar B^* with the cusps creates peaks a few MeV higher in Bbar-B^* and B^*bar-B^*, and these peaks can de-excite to piplus-piminus-Upsilon(1S,2S,3S) and piplus-piminus-chi_b(1P,2P).

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D. V. Bugg. 2011-07-20. An explanation of Belle states Z_b(10610) and Z_b(10650). https://doi.org/10.1209/0295-5075%2F96%2F11002

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