Pionic parton distributions revisited

Using constituent quark model constraints we calculate the gluon and sea-qu ark content of pions solely in terms of their valence density (fixed by pi N Drell-Yan data) and the known sea and gluon distributions of the nucleon, using the most recent updated valence-like input parton densities of the n ucleon. The resulting small-x dynamical QCD predictions for g(pi)(x, Q(2)) and (q) over bar pi(x, Q(2)) are unique and parameter free. Simple analytic parametrizations of the resulting parton distributions of the pion are pre sented in LO and NLO. These results and parametrizations will be important, among other things, for updated formulations of the parton distributions o f real and virtual photons.