Lightest Scalar in the SUL(2)xSUR(2) Linear σ Model

We consider the lightest scalar meson in the frame of the SUL(2)xSUR(2) linear σ model, keeping in mind that this model could be the low energy realization of two-flavor QCD. We show that the σ field is described by its four-quark component at least in the σ resonance energy (virtuality) region and the σ→γγ decay is the four-quark transition. We emphasize that residues of the σ pole in the ππ→ππ and γγ→ππ amplitudes do not give an idea about the σ meson nature, and the progress in studying the σ meson production mechanisms in different processes could essentially further us in understanding its nature