Background] The density of most nuclei is constant in the central region and is smoothly decreasing at the surface. A depletion in the central part of the nuclear density can have nuclear structure effects leading to the formation of "bubble’’ nuclei. However, probing the density profile of the nuclear interior is, in general, very challenging. [Purpose] The aim of this paper is to investigate the nuclear bubble structure, with nucleon-nucleus scattering, and quantify the effect that has on the nuclear surface profile. [Method] We employed high-energy nucleon-nucleus scattering under the aegis of the Glauber model to analyze various reaction observables, which helps in quantifying the nuclear bubble. The effectiveness of this method is tested on ${}^{28}$Si with harmonic-oscillator (HO) densities, before applying it on even-even $N=14$ isotones, in the $22\le A\le 34$ mass range, with realistic densities obtained from antisymmetrized molecular dynamics (AMD). [Results] Elastic scattering differential cross sections and reaction probability for the proton-${}^{28}$Si reaction are calculated using the HO density to design tests for signatures of nuclear bubble structure. We then quantify the degree of bubble structure for $N=14$ isotones with the AMD densities by analyzing their elastic scattering at 325, 550 and 800 MeV incident energies. The present analyses suggest ${}^{22}$O as a candidate for a bubble nucleus, among even-even $N=14$ isotones, in the $22\le A\le 34$ mass range. [Conclusion] We have shown that the bubble structure information is imprinted on the nucleon-nucleus elastic scattering differential cross section, especially in the first diffraction peak. Bubble nuclei tend to have a sharper nuclear surface and deformation seems to be a hindrance in their emergence.

中文翻译：

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核-核衍射中核气泡的印记

背景技术大多数核的密度在中心区域是恒定的，并且在表面平滑地下降。核密度中部的耗尽会产生核结构效应，导致“气泡”核的形成，但是，探测核内部的密度分布通常是非常困难的。 【方法】在Glauber模型的支持下，采用高能核子核散射技术，对核气泡的结构进行了研究，定量分析了其对核表面轮廓的影响。可观察到的反应，这有助于量化核气泡。${}^{28}$具有谐波振荡器（HO）密度的Si，然后将其应用于偶数偶数 $ñ=14$ 异构体 $22\le \mathrm{一种}\le 34$质量范围，并具有从反对称分子动力学（AMD）获得的实际密度。[结果]质子-的弹性散射微分截面和反应概率${}^{28}$使用HO密度计算Si反应，以设计测试核气泡结构的特征。然后我们量化气泡结构的程度$ñ=14$通过分析其在325、550和800 MeV入射能量下的弹性散射来确定具有AMD密度的同分异构体。目前的分析表明${}^{22}$O是偶数个气泡核的候选者 $ñ=14$ 异构体 $22\le \mathrm{一种}\le 34$质量范围。[结论]我们已经显示，气泡结构信息印在核-核弹性散射微分截面上，尤其是在第一个衍射峰上。气泡核倾向于具有更尖锐的核表面，并且变形似乎是其出现的障碍。