AI 中文总结
本研究结合DRHBc理论与Glauber模型，提出半唯象核心+单/双中子描述，提取镁同位素中子半径，验证了37Mg的单中子晕结构，预测40Mg具有双中子晕状结构。
AI 中文摘要
结合形变连续介质相对论哈特利-福克-博戈留波夫理论（DRHBc）计算得到的镁（Mg）同位素电荷半径，我们在Glauber模型框架下，通过研究240 MeV/核子能量下12C靶引起的反应截面（σR），提取了24-38Mg同位素的中子半径。计算采用了两种方案：（i）基于包含简谐振子单粒子波函数的斯莱特行列式（SDHO）对原子核进行描述；（ii）采用双参数费米（2pF）形状的密度分布，旨在评估24-38Mg同位素中子皮的密度依赖性。为理解中子分布的渐近行为（扩展程度），我们提议对稳定及不稳定同位素采用核心+单中子（Sn<S2n）或核心+双中子（Sn>S2n）的描述方式；其中Sn（S2n）为所研究同位素的单中子（双中子）分离能，核心+单中子（核心+双中子）采用半唯象处理。本研究中，对25-38Mg同位素采用核心+单中子描述，以复现从σR计算得到的给定同位素的中子半径。为验证核心+单中子描述的合理性，我们重新计算了25-38Mg同位素的反应截面，结果与实验值吻合良好。此外，核心+单中子的中子分布清晰展现了37Mg的单中子晕结构。这些发现促使我们采用核心+双中子描述来预测40Mg的中子半径，以及其在240 MeV/核子和1000 MeV/核子能量下与12C靶反应的σR。中子半径与σR的变化趋势表明，40Mg具有双中子晕状结构。
英文摘要
Involving the charge radii of \rm Mg isotopes, as calculated using the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), we have extracted the neutron radii of $^{24-38}$\rm Mg isotopes by studying their reaction cross sections ($σ_{R}$) from $^{12}$\rm C at 240 MeV/nucleon within the framework of Glauber model. The calculations use (i) descriptions of nuclei in terms of the Slater determinant involving harmonic oscillator single-particle wave functions (SDHO), and (ii) two-parameter Fermi (2pF) shape of density distribution, with the aim to assess the density dependence of neutron skin in $^{24-38}$\rm Mg isotopes. To understand the asymptotic behavior (spread) of neutron distribution, we propose to introduce the use of core+n ($S_{n}<S_{2n}$) or core+2n ($S_{n}>S_{2n}$) description for stable as well as unstable isotopes; $S_{n}$ ($S_{2n}$) is the one-neutron (two-neutron) separation energy of the considered isotope. The core+n (core+2n) is treated semi-phenomenologically. In this work, the core+n is employed for $^{25-38}$\rm Mg isotopes, and is subjected to reproduce the same neutron radius of the given isotope, as we obtained from $σ_{R}$ calculations. To validate the core+n description, we have revisited the reaction cross sections of $^{25-38}$\rm Mg isotopes. The results are found to agree well with the experimental values. Moreover, the core+n neutron distributions clearly demonstrate the one-neutron halo structure of $^{37}$\rm Mg. These findings motivated us to use the core+2n description for the neutron distribution of $^{40}$\rm Mg in predicting its neutron radius, and $σ_{R}$ from $^{12}$\rm C at 240 and 1000 MeV/nucleon. The trend of the neutron radius and $σ_{R}$ suggests that $^{40}$\rm Mg exhibits two-neutron halo like structure.
