  We extend the QCD sum rule analysis of the \gamma^*\gamma^* -->\pi^o form
factor into the region where one of the photons has small virtuality: q^2 <<
Q^2 > 1 GeV^2. In this kinematics, one should perform an additional
factorization of short- and long-distance contributions. The extra
long-distance sensitivity of the three-point amplitude is described by
two-point correlators (bilocals), and the low-momentum dependence of the
correlators involving composite operators of two lowest twists is extracted
from auxiliary QCD sum rules. Our estimates for the form factor at q^2=0, Q^2 >
1 1 GeV^2 are in good agreement with existing experimental data.

High Energy Physics - Phenomenology