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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 $|H\rangle =([su][\bar s
\bar u]+[sd][\bar s \bar d])/\sqrt 2$ and light $|L\rangle =[ud][\bar u \bar
d]$ scalar diquark-antidiquark components. We extract from corresponding sum
rules the mixing angles $\varphi_H$ and $\varphi_L$ of these states and
evaluate the masses and couplings of the particles $f_0(500)$ and $f_0(980)$.
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