Models for the polarized parton distributions of the nucleon

Polarized deep inelastic scattering (DIS) data are analyzed in leading and next-to-leading order of QCD within the common ``standard'' scenario of polarized parton distributions with a flavor-symmetric light sea (antiquark) distribution δq¯, and a completely SU(3)<sub>f</sub> broken ``valence'' scenario with totally flavor-asymmetric light sea densities (δū≠δd¯≠δs¯). The latter flavor-broken light sea distributions are modeled with the help of a Pauli-blocking ansatz at the low radiative or dynamical input scales of μ²_LO(NLO)=0.26 (0.40) GeV² which complies with predictions of the chiral quark-soliton model and expectations based on the statistical parton model as well as with the corresponding, well established, flavor-broken unpolarized sea (d¯>ū). Present semi-inclusive DIS data cannot yet uniquely discriminate between those two flavor-symmetric and flavor-broken polarized light sea scenarios.