Decays of fully beauty scalar tetraquarks to $B_q{\overline{B}}_q$ and $B_q^{\ast }{\overline{B}}_q^{\ast }$ mesons

Abstract

Decays of the fully beauty four-quark structures $X_{4b}$ and $T_{4b}$ to $B$ meson pairs are investigated in the framework of QCD three-point sum rule method. We model the scalar exotic mesons $X_{4b}$ and $T_{4b}$ as diquark-antidiquark systems composed of the axial-vector and pseudoscalar diquarks, respectively. The masses $m=(18540\pm 50)\mathrm{MeV}$ and $\tilde{m}=(18858\pm 50)\mathrm{MeV}$ of these compounds calculated in our previous articles, fix possible decay channels of these particles. In the present work, we consider their decays to $B_q{\overline{B}}_q$ and $B_q^{\ast }{\overline{B}}_q^{\ast }(q=u,d,s,c)$ mesons. In the case of $X_{4b}$ the mass of which is below the $2{\eta }_b$ threshold, these channels determine essential part of its full width ${\Gamma }_{4b}$. The tetraquark $T_{4b}$ can decay to the pair ${\eta }_b{\eta }_b$, therefore partial widths of processes with $B(B^{\ast })$ mesons in the final state permit us to refine our estimate for the full width of this particle. The predictions ${\Gamma }_{4b}=(9.6\pm 1.1)\mathrm{MeV}$ and ${\tilde{\Gamma }}_{4b}^{\mathrm{Full}}=(144\pm 29)\mathrm{MeV}$ obtained in this article can be used in future experimental investigations of four $b$-quark mesons.

Comments: 9 Pages, 3 Figures and 1 Table