  The spectrum of $q^2\bar q^2, J^p=0^+,2^+$ mesons is discussed. We have shown
that due to instanton - induced forces the physical states are strong mixtures
of the $SU_f(3)$ group basis states. The cross-sections for annihilation of the
$N\bar N$ system into $(q^2\bar q^2)(q\bar q)$ mesons are obtained. The
$a_0(980)$ meson is considered as $q^2\bar q^2$ meson consisting of $9_f$ and
$36_f$ plets. The branchings are also predicted for the cross-sections for
production of the $a_0(980)$ and tensor $q^2\bar q^2$ mesons in $N\bar N$
annihilation.
