标题： 非弹性$α$+$^{12}$C 散射中 Hoyle 态的缺失单极子强度 显示英文标题

标题： Missing monopole strength of the Hoyle state in the inelastic $α$+$^{12}$C scattering

摘要： 对中等能量下$\alpha$+$^{12}$C 的非弹性散射分析表明，Hoyle 态（7.65 MeV 处的同位旋标量 0$^+_2$激发态在$^{12}$C 中）的强度似乎仅耗尽了单极能量加权和规则（EWSR）的 7 到 9%，而相比之下，从非弹性电子散射数据中提取的 EWSR 约为 15%。由真实的微观$\alpha$-簇模型预测的 Hoyle 态的完整单极跃迁强度可以显示，它最多可耗尽 EWSR 的 22%。 为探索非弹性$\alpha$+$^{12}$C 散射中的缺失单极强度，我们使用基于核物质的 Brueckner Hartree Fock 结果重新参数化的复数密度依赖的 M3Y 相互作用，以及通过 Kamimura 得到的 Hoyle 态的 3-$\alpha$振荡集团波函数，在$E_{\rm lab}=104$到 240 MeV 能量范围内对非弹性$\alpha$+$^{12}$C 散射进行了完全微观的折叠模型分析。 我们的折叠模型分析显示，Hoyle态的缺失单极强度并不与$\alpha$+$^{12}$C散射分析中的不确定性相关，而更可能是由于该态的短寿命和弱结合结构，这显著增强了出口$\alpha$+$^{12}$C$^*(0^+_2)$通道的吸收。 显示英文摘要

摘要： Analyses of the inelastic $\alpha$+$^{12}$C scattering at medium energies have indicated that the strength of the Hoyle state (the isoscalar 0$^+_2$ excitation at 7.65 MeV in $^{12}$C) seems to exhaust only 7 to 9% of the monopole energy weighted sum rule (EWSR), compared to about 15% of the EWSR extracted from inelastic electron scattering data. The full monopole transition strength predicted by realistic microscopic $\alpha$-cluster models of the Hoyle state can be shown to exhaust up to 22% of the EWSR. To explore the missing monopole strength in the inelastic $\alpha$+$^{12}$C scattering, we have performed a fully microscopic folding model analysis of the inelastic $\alpha$+$^{12}$C scattering at $E_{\rm lab}=104$ to 240 MeV using the 3-$\alpha$ resonating group wave function of the Hoyle state obtained by Kamimura, and a complex density-dependent M3Y interaction newly parametrized based on the Brueckner Hartree Fock results for nuclear matter. Our folding model analysis has shown consistently that the missing monopole strength of the Hoyle state is not associated with the uncertainties in the analysis of the $\alpha$+$^{12}$C scattering, but is most likely due to the short lifetime and weakly bound structure of this state which significantly enhances absorption in the exit $\alpha$+$^{12}$C$^*(0^+_2)$ channel.