On the $\pi\pi$ contribution to the QCD sum rules for the light tetraquark

We perform a QCD sum rule analysis for the light tetraquark taking into account the contribution arising from the two pion intermediate state. We demonstrate that the interpolating current of maximum chirality, constructed from the currents of different chiral combinations of scalar and pseudoscalar diquarks, has a large coupling to the two pion state. On the contrary the current with zero chirality has only a weak coupling to this state. The possibility of using of these currents as interpolating currents for $f_0(600)$--meson is discussed