标题： 用重离子碰撞中的极端碰撞几何方法探测中子皮 显示英文标题

标题： Probing the Neutron Skin with Extreme Collision Geometries in Heavy-Ion Collisions

摘要： 理解质子和中子在原子核中的不同分布可以提供关于核结构的基本信息，并对天体物理学有深远的影响。 对这一重要差异的精确确定，通常通过所谓的中子皮厚度来量化，这在理论上和实验上都是具有挑战性的。 在这里，我们展示如何利用重离子碰撞中的一类新可观测量，通过利用超中央碰撞中旁观核子的中子和质子之间的不对称性以及边缘碰撞中参与核子的不对称性，来探测像$^{208}$Pb 和$^{48}$Ca 这样的核的中子皮厚度。 通过定量模拟，我们证明了它们在这些极端事件几何条件下对$^{208}$Pb 和$^{48}$Ca 核的中子皮厚度的约束能力及其巨大的潜力。 此外，我们提出 $^{48}$Ca 和$^{40}$Ca 核之间的不对称碰撞作为一种独特而有效的方法，以准确确定中子皮厚度。 显示英文摘要

摘要： Understanding how protons and neutrons are located differently in an atomic nucleus can provide fundamental information on nuclear structure and have far-reaching implications for astrophysics. A precise determination of this important difference, often quantified by the so-called neutron skin thickness, is challenging both theoretically and experimentally. Here we show how one can use a new category of observables in heavy ion collisions to probe the neutron skin thickness of nuclei like $^{208}$Pb and $^{48}$Ca, by utilizing the asymmetry between neutrons and protons of spectator nucleons in super-central collisions as well as that of participant nucleons in peripheral collisions. Using quantitative simulations, we demonstrate their sensitivity and great potential in constraining neutron skin thickness for both $^{208}$Pb and $^{48}$Ca nuclei in these extreme event geometries. Furthermore, we propose the asymmetric collisions between $^{48}$Ca and $^{40}$Ca nuclei as a unique and powerful way to nail down the neutron skin thickness.