Polarized sea-quark and gluon distribution functions

Abstract

With the phenomenologically determined valence-quark spin densities in conjunction with the positivity of the unpolarized parton distributions, we extract the polarized sea-quark (gluon) distribution necessary to interpret the European Muon Collaboration measurement of the polarized proton structure function $g_1^p\mathrm{}\left(x\right)\mathrm{}$ in terms of sea quarks (gluons) alone. We then propose more realistic spin-dependent sea and gluon distribution functions which are parametrized in such a way that the first moment of $g_1^p\mathrm{}\left(x\right)\mathrm{}$ receives almost all contributions from the region $x>\mathrm{}0.01\mathrm{}$. A prediction of the polarized neutron structure function is given.