Scaling and four-quark fragmentation

The conditions for a scaling behaviour from the fragmentation process leading to slow protons are discussed. The scaling referred to implies that the fragmentation functions depend on the light-cone momentum fraction only. It is shown that differences in the fragmentation functions for valence- and sea-quark knock out give rise to scaling violations. It is proposed that these scaling violations are measured experimentally to put constraints on the four-quark fragmentation functions. Estimates suggest that with reasonable assumptions for the fragmentation functions large effects are to be expected. (orig.)