On the W and Q2 dependence of fragmentation functions as measured in leptoproduction

Some problems and questions related to the W (hadronic effective mass) and Q2 (four-momentum transfer) dependence of fragmentation functions as measured in leptoproduction are discussed. The main results obtained on this subject in previous experiments are reviewed. New data on νp and ν-barp scattering from a BEBC experiment suggest that in the present energy range fragmentation functions depend on W and (at fixed W) not on Q2. The increase of particle production with increasing W seems to occur only at small Feynman-xF, i.e. in the central region, suggesting that it is mainly due to the kinematical widening of the available rapidity range with increasing W. 27 refs., 5 figs. (author)