  Diffractive dissociation of particles can be used to study their light-cone
wave functions. Results from Fermilab experiment E791 for diffractive
dissociation of 500 GeV/c pi- mesons into di-jets show that the |q qbar>
light-cone asymptotic wave function describes the data well for Q^2 ~ 10
(GeV/c)^2 or more.
