Spectroscopic parameters and decays of the resonance $Z_b(10610)$

Abstract

The resonance $Z_b(10610)$ is investigated as the diquark-antidiquark $ Z_b=[bu][\overline b \overline d]$ state with spin-parities $J^{PC}=1^{+-}$. The mass and current coupling of the resonance $Z_b(10610)$ are evaluated using QCD two-point sum rule and taking into account the vacuum condensates up to ten dimensions. We study the vertices $ Z_b\Upsilon(nS)\pi\ (n=1,2,3)$ by applying the QCD light-cone sum rule to compute the corresponding strong couplings $g_{Z_b\Upsilon(nS)\pi}$ and widths of the decays $Z_b \to \Upsilon(nS)\pi$. We explore also the vertices $Z_b h_{b}(mP)\pi\ (m=1,2)$ and calculate the couplings $g_{Z_b h_{b}(mP)\pi}$ and width of the decay channels $Z_b \to h_{b}(mP)\pi$. To this end, we calculate the mass and decay constants of the $h_b(1P)$ and $h_b(2P) $ mesons. The results obtained are compared with experimental data of the Belle Collaboration.