Smearing corrections on deuterium targets

In this paper we show and clarify further the consistency (which in the conventional, non-relativistic approach is lacking) of the recent, simple, spinless and relativistic approach (the nucleon-parton approach) to Fermi motion effects on deuterium targets. In analysing the recent high-energy cross-section data of πD, πN and ND, NN processes, we find that the conventional approach leads to a non-negligible smearing correction sigmasub(s). On the other hand, the nucleon-parton approach, by using a simple ansatz for the truncated n-p-d relativistic vertex function, leads to a vanishing sigmasub(s). We show, also, that the inclusion of a spin degree of freedom in the formalism for leptonic scattering, where smearing effects are very important, does not affect the previous (spinless) results. (orig.)