Semi-inclusive production of pions in DIS and $\bar d - \bar u$ asymmetry

Abstract

We discuss the role of some nonpartonic effects which lead to $N_p^{π^+} \ne N_n^{π^+}$ and $N_p^{π^-} \ne N_n^{π^-}$ and may therefore modify the conclusionon the $\bar d - \bar u$ asymmetry extracted from semi-inclusive production of pions in DIS. Quantitative estimations for resolved photon and exclusive $ρ^0$ are given as examples. The results are discussed in the context of recent HERMES data.