Bound state nature of the exotic Z_b states
| Autor: | Martin Cleven, Ulf-G. Meißner, Feng-Kun Guo, Christoph Hanhart |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
bound state [meson]
Nuclear and High Energy Physics Particle physics Nuclear Theory Meson Binding energy Hadron FOS: Physical sciences mass [Upsilon(10870)] High Energy Physics - Experiment nonrelativistic [effective field theory] Nuclear Theory (nucl-th) High Energy Physics - Experiment (hep-ex) Z/b(10610) High Energy Physics - Phenomenology (hep-ph) Bound state Nuclear fusion ddc:530 mass spectrum [quarkonium] Nuclear theory Z/b(10650) Physics exotic [meson] binding energy Breit-Wigner 2 [higher-order] High Energy Physics - Phenomenology molecule [meson meson] bottom meson Parametrization Bar (unit) |
| Zdroj: | The European physical journal / A 47, 120 (2011). doi:10.1140/epja/i2011-11120-6 |
| DOI: | 10.48550/arxiv.1107.0254 |
| Popis: | The assumption that the newly observed charged bottomonia states Z_b(10610) and Z_b(10650) are of molecular nature is confronted with the measured invariant mass distributions for the transitions of the Upsilon(5S) to the final states h_b pi^+ pi^- and h_b(2P) pi^+ pi^-. It is shown that the assumption that the Z_b(10610) and Z_b(10650) are B\bar B^*+{\rm c.c.} and B^*\bar B^* bound states, respectively, with very small binding energies is consistent with the data. The calculation is based on a power counting for bottom meson loops, which is explicitly given up to two-loop in the framework of a nonrelativistic effective field theory. We also show that if the Z_b states are of molecular nature, then the data should not be analyzed by using a Breit-Wigner parametrization. Comment: 8 pages, 5 figures. Typos corrected, version appeared in Eur. Phys. J. A |
| Databáze: | OpenAIRE |
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