Isospin distributions in the proton and the Gottfried sum rule from leptoproduction of hadrons

Abstract

We investigate the implications for the production of hadrons of the asymmetry in the proton sea distribution, i.e. ū(x)≠ d̄(x), found recently by the New Muon Collaboration. The resulting “deviations” in the cross sections for the production of charged pions and, more general, charged hadrons are of the same order of magnitude as those in inclusive processes. Hence semi-inclusive data can provide an additional check on the Gottfried sum rule.