Gottfried sum rule in QCD NS analysis of DIS fixed target data

Abstract

Deep inelastic scattering data on $F_2$ structure function obtained in the fixed-target experiments were analysed in the valence quark approximation with a next-to-next-to-leading-order accuracy. Parton distribution functions are parametrized by using information from the Gottfried sum rule. The strong coupling constant is found to be ${\alpha }_s(M_Z^2)=0.1180\pm 0.0020\text{mbox}(totalexp.error)$, which coincides very well with the average world value ${\alpha }_s^{\mathrm{PDG}}(M_Z^2)=0.1181\pm 0.0013$ updated recently in a PDG report. The result for the second moment of the difference in $u$ and $d$ quark distributions $<x{>}_{u-d}=0.187\pm 0.021$ is seen to be well compatible with the latest LATTICE result $<x{>}_{u-d}^{\mathrm{LATTICE}}=0.208\pm 0.024$

Comments: 12 pp, 1 fig, version to be published in Phys. At. Nucl