The structure, mixing angle, mass and couplings of the light scalar $f_0(500)$ and $f_0(980)$ mesons

The mixing angle, mass and couplings of the light scalar mesons $f_0(500)$ and $f_0(980)$ are calculated in the framework of QCD two-point sum rule approach by assuming that they are tetraquarks with diquark-antidiquark structures. The mesons are treated as mixtures of the heavy $|H\rangle =([su][\bar s \bar u]+[sd][\bar s \bar d])/\sqrt 2$andlight$|L\rangle =[ud][\bar u \bar d]$ scalar diquark-antidiquark components. We extract from corresponding sum rules the mixing angles ${\phi }_H$ and ${\phi }_L$ of these states and evaluate the masses and couplings of the particles $f_0(500)$ and $f_0(980)$.