QCD Analysis of the semi-inclusive HERMES and COMPASS data

Abstract

Theˇrst moments of polarized valence PDFs, responsible for the respective contributions to the nucleon spin, are extracted in NLO QCD from the data of COMPASS and HERMES Collaborations on the semi-inclusive difference asymmetries. To this end, the new method of QCD analysis (alternative to the usual globalˇt analysis) is applied. Using the obtained results on valence PDFs, theˇrst moments of polarized sea PDFs are reconstructed. They occur surprisingly small: compatible with zeros within the errors.