Imprint of the adjoint meson spectrum in the decay patterns of hidden-bottom tetraquarks

Abstract

We aim to clarify the experimentally observed near-degeneracy and decay patterns of the isospin, $I=1$, hidden-bottom tetraquarks $Z_b(10610)$ and $Z_b(10650)$ with quantum numbers $J^P=1^{+}$.We refer to them as $Z_b$ and $Z_b^{{}^{\prime }}$, respectively. In particular, we find first evidence that the suppression of the decay of $Z_b^{{}^{\prime }}$ to $B\overline{B^{\ast }}$ can be understood in the context of the Born-Oppenheimer Effective Field Theory (BOEFT). BOEFT enables writing both $Z_b$ and $Z_b^{{}^{\prime }}$ as superpositions of $Z_1$ and $Z_2$ tetraquark configurations. This decomposition naturally relates the decay patterns of $Z_b$ and $Z_b^{{}^{\prime }}$ to the degeneracy of the light degrees of freedom associated with $Z_1$ and $Z_2$ tetraquarks, {\it i.e.,} $1^{--}$and $0^{-+}$ adjoint mesons, respectively. By calculating the adjoint meson correlators within the framework of lattice QCD, we get good indications that these adjoint mesons are degenerate.

Comments: 10 pages, 1 figure, Contribution to The 42nd International Symposium on Lattice Field Theory (LATTICE2025). Version accepted by PoS Lattice 2025