Instanton model of light hadrons: from low to high energies

Abstract

Instanton liquid model being effective model of the QCD vacuum describes well the hadrons at low as well at intermediate energies. Thus, contact with perturbative QCD results is possible providing the unique information about the quark-gluon distribution functions in the QCD vacuum and hadrons at low energy normalization point. As an illustrative example we consider the pion transition form factor for the process ${\gamma }^{\ast }{\gamma }^{\ast }\to {\pi }^0$ at space-like values of photon momenta. The leading and next-to-leading order power asymptotics of the form factor and the relation between the light-cone pion distribution amplitudes of twists 2 and 4 and the dynamically generated quark mass are found.

Comments: 4 pages, laTex; 2 eps figures; Talk given at XXXII International Simposium on Multiparticle Dynamics, September 7-13, Alushta, Crimea, Ukraine