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 $N_p^{{\pi }^{+}}\ne N_n^{{\pi }^{+}}$ and $N_p^{{\pi }^{-}}\ne N_n^{{\pi }^{-}}$ 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 ${\rho }^0$ are given as examples. The results are discussed in the context of recent HERMES data.

Comments: A talk given at the workshop "Meson2000", Cracow, Poland, 19-23 May 2000