Testing target independence of the ‘proton spin’ effect in semi-inclusive deep-inelastic scattering Original Research Article

A natural consequence of the composite operator propagator-vertex description of deep-inelastic scattering developed by the authors is that the anomalous suppression observed in the flavour singlet contribution to the first moment of the polarised proton structure function g1p (the ‘proton spin’ problem) is not a special property of the proton structure but is a target-independent effect which can be related to an anomalous suppression in the QCD topological susceptibility. In this paper it is shown how this target-independent mechanism can be tested in semi-inclusive deep-inelastic scattering in which a pion or D meson carrying a large target energy fraction z is detected in the target fragmentation region.