HIDDEN SECTORS WITH HIDDEN MATTER

Using previous results on non-perturbative effects in massive supersymmetric Yang-Mills theories, we extend recent considerations on the duality invariant guagino condensation, within the string effective action approach, to the formation of hidden matter field condensates. The masses of the condensing matter fields are determined by some string background parameters corresponding to vacuum expectation values of additional gauge singlet hidden matter fields. The vacuum degeneracy of these fields is shown to be lifted by non-perturbative condensation effects.