Perturbative generation of a strange-quark asymmetry in the nucleon

Abstract

The perturbative evolution in QCD at three loops generates a stragne-antistrang asymmetry in the nucleons was analyzed. It was found that non-singlet evolution of the parton densities at three loops generates a strange asymmetry even if it was not present at the input scale. It was also observed that the effect arises because at that order of perturbation theory the probability of splitting q → q-1 and became different from that of q → q-1 and because the nucleon has u and d valence densities. The results show that the asymmetries were smaller than in the strange sector, mostly due to the larger initial scale.