Heavy axial-vector structures

The fully heavy axial-vector diquark-antidiquark structures $bb\stackrel{‾}{c}\stackrel{‾}{c}$ are explored by means of the QCD sum rule method. They are modeled as four-quark mesons ${T}_{1}$ and ${T}_{2}$ composed of ${b}^{T}C{\sigma }_{\mu \nu }{\gamma }_{5}b$, $\stackrel{‾}{c}{\gamma }^{\nu }C{\stackrel{‾}{c}}^{T}$ and ${b}^{T}C{\gamma }_{\mu }{\gamma }_{5}b$, $\stackrel{‾}{c}C{\stackrel{‾}{c}}^{T}$ diquarks, respectively. The spectroscopic parameters of the tetraquarks ${T}_{1}$ and ${T}_{2}$ are determined in the context of the QCD two-point sum rule method. Results obtained for masses of these states ${m}_{1}=\left(12715±86\right)\phantom{\rule{0.25em}{0ex}}\mathrm{MeV}$ and ${m}_{2}=\left(13383±92\right)\phantom{\rule{0.25em}{0ex}}\mathrm{MeV}$ are used to fix their strong decay channels. The full width $\Gamma \left({T}_{1}\right)$ of the diquark-antidiquark state ${T}_{1}$ is estimated by considering the processes ${T}_{1}\to {B}_{c}^{-}{B}_{c}^{⁎-}$ and ${T}_{1}\to {B}_{c}^{⁎-}{B}_{c}^{⁎-}$. The decays to mesons ${B}_{c}^{-}{B}_{c}^{⁎-}$, ${B}_{c}^{-}\left(2S\right){B}_{c}^{⁎-}$ and ${B}_{c}^{⁎-}{B}_{c}^{⁎-}$ are employed to evaluate $\Gamma \left({T}_{2}\right)$. Results obtained for the widths $\Gamma \left({T}_{1}\right)=\left(44.3±8.8\right)\phantom{\rule{0.25em}{0ex}}\mathrm{MeV}$ and $\Gamma \left({T}_{2}\right)=\left(82.5±13.7\right)\phantom{\rule{0.25em}{0ex}}\mathrm{MeV}$ of these tetraquarks in conjunction with their masses are useful for future experimental studies of fully heavy resonances.