We analyze the pion-exchange contribution to semi-inclusive leptoproduction on protons, with a slow nucleon or delta in the final state. We calculate the crosssection for slow protons including also the effect of the delta intermediate state, which is the dominant contribution. A comparison with recent experiment shows reasonable agreement for small Bjorken x, if the cut-off in the pion-nucleon-delta form-factor is chosen to be around 0.7 GeV. This substantiates the recent conjecture that sea-quark distributions can be completely associated with the meson cloud, but suggests that the pion-nucleon-delta form-factor should be softer than the one used in description of nuclear forces by meson exchange. We also compare the pion-exchange and the string-fragmentation models and point out possible future experimental tests.
ASJC Scopus subject areas
- Nuclear and High Energy Physics