论文标题
$^{16} $ o+$^{12} $ c散射及其对核彩虹的影响
Elastic $α$ transfer in the $^{16}$O+$^{12}$C scattering and its impact on the nuclear rainbow
论文作者
论文摘要
已知弹性$^{16} $ o+$^{12} $ c散射在事件能量处展示核彩虹图案$ e_ \ text {lab} \ gtrsim 200 $ mev，远处散射交叉部分的空气结构清晰可见。通过双重折叠模型（DFM）给出的深层真实光电位（OP）很好地描述了这种彩虹图案。在较低的能量下，广泛的弹性$^{16} $ o+$^{12} $ c散射数据一致地表明，通过在常规光学模型中难以描述的弹性横截面的振荡增强，向后角的核彩虹模式降低了。 Given a significant $α$ spectroscopic factor predicted for the dissociation $^{16}$O$\toα+^{12}$C by the shell model and $α$-cluster models, the contribution of the elastic $α$ transfer (or the core-core exchange) to the elastic $^{16}$O+$^{12}$C scattering should not be negligible and is expected to account for the enhanced向后角的弹性横截面。为了揭示弹性$α$转移的影响，已经对弹性$^{16} $ o+$+$^{12} $ c散射进行了系统的耦合反应通道分析，并使用DFM的真实OP进行了弹性散射和弹性$α$转移通道之间的耦合。我们发现，弹性$α$转移在向后角度显着增强了近侧散射，从而导致光滑的通风结构的振荡失真。通过弹性散射和弹性$α$转移通道之间的耦合，可以有效地考虑到添加到虚构OP中的Angular Momentum（或平等）依赖性电位，如Frahn和Hussein 40年前所建议的那样，可以有效地考虑OP的动态极化。
Elastic $^{16}$O+$^{12}$C scattering is known to exhibit the nuclear rainbow pattern at incident energies $E_\text{lab}\gtrsim 200$ MeV, with the Airy structure of the far-side scattering cross section clearly seen at medium and large angles. Such a rainbow pattern is well described by the deep real optical potential (OP) given by the double-folding model (DFM). At lower energies, the extensive elastic $^{16}$O+$^{12}$C scattering data show consistently that the nuclear rainbow pattern at backward angles is deteriorated by an oscillating enhancement of elastic cross section that is difficult to describe in the conventional optical model (OM). Given a significant $α$ spectroscopic factor predicted for the dissociation $^{16}$O$\toα+^{12}$C by the shell model and $α$-cluster models, the contribution of the elastic $α$ transfer (or the core-core exchange) to the elastic $^{16}$O+$^{12}$C scattering should not be negligible and is expected to account for the enhanced elastic cross section at backward angles. To reveal the impact of the elastic $α$ transfer, a systematic coupled reaction channels analysis of the elastic $^{16}$O+$^{12}$C scattering has been performed, with the coupling between the elastic scattering and elastic $α$ transfer channels treated explicitly, using the real OP given by the DFM. We found that the elastic $α$ transfer enhances the near-side scattering significantly at backward angles, giving rise to an oscillating distortion of the smooth Airy structure. The dynamic polarization of the OP by the coupling between the elastic scattering and elastic $α$ transfer channels can be effectively taken into account in the OM calculation by an angular-momentum (or parity) dependent potential added to the imaginary OP, as suggested by Frahn and Hussein 40 years ago.
