标题： 相关双π介子交换在$K^+ N$散射中的作用 显示英文标题

标题： Role of correlated two-pion exchange in $K^+ N$ scattering

摘要： 一个用于K介子和核子之间S-波和P-波相关$2 \pi$（和$K \bar K$）交换的动力学模型被提出，从对应的伪物理区域中的$N \bar N \rightarrow K \bar K$振幅开始，这些振幅由核子、$\Delta$-π介子和超子（$\Lambda$，$\Sigma$）交换的Born项以及真实的介子交换模型中的$\pi \pi \rightarrow K \bar K$和$K \bar K \rightarrow K \bar K$振幅构建而成。 通过在单位性切割上进行色散关系，可以得到s-通道的贡献。 在$\rho$-通道中，存在较大的不确定性，这取决于如何进行色散积分。 我们的模型，加上短程相互作用项，能够满意地描述介子产生阈值以下的经验$K^+ N$数据。 显示英文摘要

摘要： A dynamical model for S-- and P--wave correlated $2 \pi$ (and $K \bar K$) exchange between a kaon and a nucleon is presented, starting from corresponding $N \bar N \rightarrow K \bar K$ amplitudes in the pseudophysical region, which have been constructed from nucleon, $\Delta$--isobar and hyperon ($\Lambda$, $\Sigma$) exchange Born terms and a realistic meson exchange model of the $\pi \pi \rightarrow K \bar K$ and $K \bar K \rightarrow K \bar K$ amplitude. The contribution in the s--channel is then obtained by performing a dispersion relation over the unitarity cut. In the $\rho$--channel, considerable ambiguities exist, depending on how the dispersion integral is performed. Our model, supplemented by short range interaction terms, is able to describe empirical $K^+ N$ data below pion production threshold in a satisfactory way.