Zb tetraquark channel from lattice QCD and Born-Oppenheimer approximation
| Autor: | Prelovsek, S., Bahtiyar, H., Petkovic, J. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Lett. B 805 (2020) 135467 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.physletb.2020.135467 |
| Popis: | Two $Z_b$ hadrons with exotic quark structure $\bar bb\bar du$ were discovered by Belle experiment. We present a lattice QCD study of the $\bar bb\bar du$ system in the approximation of static $b$ quarks, where the total spin of heavy quarks is fixed to one. The energies of eigenstates are determined as a function of the separation $r$ between $b$ and $\bar b$. The lower eigenstates are related to a bottomonium and a pion. The eigenstate dominated by $B\bar B^*$ has energy significantly below $m_B+m_{B^*}$, which points to a sizable attraction for small $r$. The attractive potential $V(r)$ between $B$ and $\bar B^*$ is extracted assuming that this eigenstate is related exclusively to $B\bar B^*$. The Schr\"odinger equation for $B\bar B^*$ within the extracted potential leads to one bound state below $B\bar B^*$ threshold, whose mass depends on the parametrization of the lattice potential. For certain parametrizations, the bound state is very close to the $B\bar B^*$ threshold and renders a narrow peak in the $B\bar B^*$ rate above threshold - these features could be related to $Z_b(10610)$ in the experiment. Comment: 5 pages and supplement. The submatrix of the correlation matrix was multiplied by a wrong overall constant, which affected the eigen-energies. All figures expect Fig. 1 are replaced in v4. The main conclusion does not change - Zb is related to attraction between B and B*. The correct potential is less attractive and it results only in one bound state (see Note added) |
| Databáze: | arXiv |
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