AI 中文总结
研究人员采用NCSM/RGM方法结合SRG分析，证实${}^4\rm{He}$中反质子湮灭主要发生在核表面，为反质子原子实验的唯象图像提供了理论支持。
AI 中文摘要
欧洲核子研究中心反质子减速器（CERN/AD）的低能反质子束为通过核表面处的湮灭探测奇特核结构提供了可能。将反质子用作核表面探针的基础假设是湮灭发生在靶核的外围。我们针对结合最紧密的轻核${}^4\rm{He}$，采用适配反质子-核动力学的从头算无芯壳模型结合共振群方法（NCSM/RGM）对该假设进行检验。在通过现有原子与散射数据验证微观计算的可靠性后，我们利用微观湮灭密度探究反质子原子内部的湮灭位置。结果发现，湮灭在${}^4\rm{He}$密度的尾部达到峰值，位于$r\rm{\thickapprox}2\rm{fm}$附近，而在核内部则被强烈抑制。尽管该密度具有表象依赖性，但对NCSM/RGM哈密顿量的相似重整化群（SRG）分析表明，低能湮灭强度仍定域在大的团簇间距处。这些结果为反质子原子实验背后的唯象图像提供了支持：在${}^4\rm{He}$这类结合紧密的系统中，反质子湮灭主要发生在表面区域，因此对核密度尾部具有敏感性。
英文摘要
Low-energy antiproton beams at CERN/AD open the possibility of probing exotic nuclear structure through annihilation at the nuclear surface. The use of antiprotons as the probe for the nuclear surface is based on the assumption that the annihilation takes place at the periphery of the target. We test this idea for the lightest tightly bound nucleus, i.e., ${}^4 \mathrm{He}$, using the ab initio no-core shell model combined with the resonating group method (NCSM/RGM), adapted to antiproton-nucleus dynamics. After validating our microscopic calculations against available atomic and scattering data, we use the microscopic annihilation density to examine where annihilation occurs inside the antiprotonic atom. We find that the annihilation peaks in the tail of the ${}^{4}\mathrm{He}$ density, around $r\approx 2$ fm, and is strongly suppressed in the nuclear interior. Although this density is representation dependent, a similarity renormalization group (SRG) analysis of the NCSM/RGM Hamiltonian shows that the low-energy annihilation strength remains localized at large intercluster distances. These results support the phenomenological picture underlying antiprotonic-atom experiments: in a tightly bound system such as ${}^{4}\mathrm{He}$, antiproton annihilation is predominantly peripheral and is therefore sensitive to the nuclear-density tail.
Comments7 pages, 7 figures, 3 tables
