标题： $\bar d - \bar u$介子在深度非弹性散射中的不对称性和半包容产生 显示英文标题

标题： $\bar d - \bar u$ asymmetry and semi-inclusive production of pions in DIS

摘要： 我们研究从深度非弹性散射中π介子的半inclusive产生中提取$\bar d - \bar u$不对称性的不确定性。 研究了超出夸克-部分子模型（QPM）的几种效应，这些效应导致$N_p^{\pi^+} \ne N_n^{\pi^+}$和$N_p^{\pi^-} \ne N_n^{\pi^-}$，并可能因此妨碍这种提取。 结果在最近的HERMES数据背景下进行讨论。 我们发现，解析光子与核子的相互作用显著改变了观察到的$\bar d - \bar u$不对称性。 $\rho$介子的独占弹性产生对于大-$z$数据样本起着类似的作用。 我们的估计显示，旁观者机制的影响相当小。 氘核中的核效应也看起来潜在重要，但难以进行定量估计。 在本文中，我们还对介子的半inclusive和独占产生提出了几个一般性备注。 显示英文摘要

摘要： We investigate unambiguities in the extraction of the $\bar d - \bar u$ asymmetry from semi-inclusive production of pions in DIS. The role of several effects beyond the quark-parton model (QPM) which lead to $N_p^{\pi^+} \ne N_n^{\pi^+}$ and $N_p^{\pi^-} \ne N_n^{\pi^-}$ and may therefore cloud such an extraction is studied. The results are discussed in the context of the recent HERMES data. We find that the interaction of the resolved photon with the nucleon significantly modifies the observed $\bar d - \bar u$ asymmetry. The exclusive elastic production of $\rho$ mesons plays a similar role for the large-$z$ data sample. Our estimate shows a rather small effect of the spectator mechanism. Nuclear effects in the deuteron also look potentially important but are difficult to estimate quantitatively. Throughout the paper we make in addition several general remarks concerning semi-inclusive and exclusive production of mesons.