The Role of Strange and Charm Quarks in the Nucleon Spin Structure Function

We perform an analysis of the relation between the factorization scale and the masses of the quarks in the calculation of the hard gluon coefficient in polarized deep inelastic scattering. Particular attention is paid to the role of strange and charm quarks at finite momentum transfer. It is found that for the momentum transfer of the present experiments, the contribution from the charm quark is significant.