  The leptonic and semileptonic decays of mesons are investigated within the
Domain model of QCD vacuum and hadronization. The Domain Model is the
mean-field approach based on the statistical ensemble of almost everywhere
homogeneous Abelian (anti-)self-dual gluon fields which reproduces main
features of low-energy QCD and allows to deduce a nonlocal effective meson
action. Using this meson action, the leptonic decay constants, form factors and
branching ratios of semileptonic decays are evaluated simultaneously with
masses of mesons. The results are compared to experimental data or other
approaches.
