标题： 质子海中的非微扰效应 显示英文标题

标题： Nonperturbative effects in the proton sea

摘要： 我们重新评估了质子结构函数中pionic机制的$\bar{u}-\bar{d}$-不对称性。 我们的分析基于不同机制对包容粒子产生和总光吸收截面（即质子结构函数）贡献之间的单位性关系。 我们重新分析了等矢量Reggeon在强子反应中核子和Delta等轴子包容产生中的作用。 发现由Reggeon交换引起的Delta等轴子产生有相当大的贡献。 这使得由介子交换引起的$\Delta$产生机制的空间大大减少，并对$\pi N \Delta$形状因子提供了约束。 质子-质子碰撞中领先介子的产生对$\pi NN$顶点形状因子施加了额外的约束。 所有这些约束随后被用来估计核子中的介子含量，并能够无参数地计算$\bar d - \bar u$的x依赖性。 我们讨论了Gottfried求和规则的破坏以及$\bar d$-$\bar u$不对称性，并与费米实验室E866实验得到的结果进行比较。 显示英文摘要

摘要： We revisit the evaluation of the pionic mechanism of the $\bar{u}-\bar{d}$-asymmetry in the proton structure function. Our analysis is based on the unitarity relation between contributions of different mechanisms to the inclusive particle production and the total photoabsorption cross-section (i.e. the proton structure function). We reanalyze the role of isovector reggeons in inclusive production of nucleons and Delta isobars in hadronic reactions. A rather large contribution of reggeon-exchange induced production of Delta isobars is found. This leaves much less room for the pion-exchange induced mechanism of $\Delta$ production and provides a constraint on the $\pi N \Delta$ form factor. The production of leading pions in proton-proton collisions puts additional constraints on the $\pi NN$ vertex form factors. All these constraints are used then to estimate the pion content of the nucleon and allow to calculate parameter-free the x-dependence of $\bar d - \bar u$. We discuss the violation of the Gottfried Sum Rule and $\bar d$-$\bar u$ asymmetry and compare to the one obtained from the E866 experiment at Fermilab.