The nonet of the light scalar tetraquarks: the mesons $a_0(980)$ and $K_{0}^{\ast }(800)$

The spectroscopic parameters and partial decay widths of the light mesons $ a_0(980) $ and $K_{0}^{\ast}(800)$ are calculated by treating them as scalar diquark-antidiquark states. The masses and couplings of the mesons are found in the framework of QCD two-point sum rule approach. The widths of the decay channels $a_0(980) \to \eta \pi$ and $a_0(980) \to K \bar{K}$, and $ K_{0}^{\ast}(800) \to K^{+} \pi^{-}$ and $K_{0}^{\ast}(800) \to K^{0} \pi^{0} $ are evaluated using QCD sum rules on the light-cone and technical tools of the soft meson approximation. Our results for the mass of the mesons $m_{a_0}=991^{+29}_{-27} \ \mathrm{MeV}$ and $m_{K^{ \ast}}=767^{+38}_{-29} \ \mathrm{MeV}$, as well as their total width $\Gamma _{\mathrm{a_0}}=62.01\pm 14.37\ \mathrm{MeV}$ and $\Gamma _{\mathrm{ K_0^{\ast}}}=401.1\pm 87.1\ \mathrm{MeV}$ are compared with last experimental data.