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 $Z_b{\rm Y}(nS)\pi (n=1,2,3)$ by applying the QCD light-cone sum rule to compute the corresponding strong couplings $g_{Z_b{\rm Y}(nS)\pi }$ and widths of the decays $Z_b\to {\rm Y}(nS)\pi$. 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.

Comments: 12 Pages, 5 Figures and 2 Tables