QCD sum rule approach for the light scalar mesons as four-quark states

We study the two point-function for the scalar mesons σ, κ, f0(980) and a0(980) as diquak-antidiquark states. We also study the decays of these mesons into ππ, Kπ and KK¯. We find that the couplings are consistent with existing experimental data, supporting the four-quark structure for the light scalar mesons.