Shares of sea and valence quarks in the proton spin puzzle
O. Yu. Shevchenko, R. R. Akhunzyanov1), V. Yu. Lavrentyev1)
Joint Institute for Nuclear Research, 141980 Dubna, Russia
The first moments of the polarized valence PDFs
truncated to the wide Bjorken x region 0.004<x<0.7
are directly (without any fitting procedure) extracted in NLO QCD from the
combined semi-inclusive DIS data of COMPASS and HERMES.
Applying the proposed original procedure to these results we
estimate the contributions
of light sea
quarks to the proton spin, which occur just zero
within the errors.