Axial-vector molecular structures $B_c^{\ast \pm }{B}_c^{\mp }$

Abstract

The axial-vector molecular structure ${\mathcal{M}}_{\mathrm{AV}}=(B_c^{\ast +}{B}_c^{-}+B_c^{\ast -}{B}_c^{+})/2$ is explored in QCD sum rule framework. The mass and current coupling of this compound are found by means of the two-point sum rule method. It turns out that the mass of ${\mathcal{M}}_{\mathrm{AV}}$ is equal to $m=(12770\pm 60)\mathrm{MeV}$ making possible its dissociations to pairs of $J/\psi {\eta }_b$, ${\rm Y}{\eta }_c$, $B_c^{\ast +}{B}_c^{-}$, and $B_c^{\ast -}{B}_c^{+}$ mesons. The partial widths of these decay modes contain the strong couplings at ${\mathcal{M}}_{\mathrm{AV}}$-meson-meson vertices which are calculated by utilizing the three-point sum rule method. The full decay width of the molecule ${\mathcal{M}}_{\mathrm{AV}}$ is formed due to these dominant processes and amounts to $\Gamma [{\mathcal{M}}_{\mathrm{AV}}]=(93\pm 14)\mathrm{MeV}$. Our results for parameters $m$ and $\Gamma [{\mathcal{M}}_{\mathrm{AV}}]$ of the hadronic molecule ${\mathcal{M}}_{\mathrm{AV}}$ are useful for experimental studies of various fully heavy four-quark mesons.

Comments: 9 Pages and 3 Figures