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

Abstract

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 $f_0(980)$.