标题： 低能散射和光致产生在三体核上的$η$-介子 显示英文标题

标题： Low-energy scattering and photoproduction of $η$-mesons on three-body nuclei

摘要： 低能$\eta$介子与三体核的散射的光学势方法与使用仅s波可分离相互作用的四体散射理论对$\eta 3N$系统的精确处理进行了比较。 包括被击中核子与周围核介质的相互作用以及在连续$\eta$散射之间的虚拟靶激发的高阶项被发现会导致重要的修正。 还研究了$\eta$光致产额在$^3$H 和$^3$He 上的末态相互作用，发现其有超出光学模型方法的显著贡献。 显示英文摘要

摘要： The optical potential approach for low-energy scattering of $\eta$-mesons on three-body nuclei is compared to an exact treatment of the $\eta 3N$ system using four-body scattering theory with separable interactions in s-waves only. The higher-order terms including the interaction of the struck nucleon with the surrounding nuclear medium and virtual target excitations in between successive $\eta$-scatterings are found to cause important corrections. Effects of final state interaction in $\eta$-photoproduction on $^3$H and $^3$He are also studied and sizable contributions beyond the optical model approach are found.