  The unitarity of the $S$-matrix requires that the absorptive part of the
elastic scattering amplitude receives contributions from both the inelastic and
the elastic channels. We explore this unitarity condition in order to describe,
in a connected way, hadron-hadron observables like the total and elastic
differential cross sections, the ratio of the real to imaginary part of the
forward scattering amplitude and the inclusive multiplicity distributions in
full phase space, over a large range of energies. We introduce non-perturbative
QCD effects in the forward scattering amplitude by using the infrared QCD
effective charge dependent on the dynamical gluon mass. In our analysis we pay
special attention to the theoretical uncertainties in the predictions due to
this mass scale variation. We also present quantitative predictions for the
$H_{q}$ moments at high energies. Our results reproduce the moment oscillations
observed in experimental data, and are consistent with the behavior predicted
by QCD.
