Probing the core of the strong nuclear interaction
Probing the core of the strong nuclear interaction
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DOI：
10.1038/s41586-020-2021-6
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发表时间：
2020-02
期刊：
影响因子：
64.8
通讯作者：
A. Schmidt;J. Pybus;R. Weiss;E. Segarra;A. Hrnjic;A. Denniston;O. Hen;E. Piasetzky;L. Wein
中科院分区：
文献类型：
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作者：
A. Schmidt;J. Pybus;R. Weiss;E. Segarra;A. Hrnjic;A. Denniston;O. Hen;E. Piasetzky;L. Wein
核子（质子和中子）之间的强核相互作用是将原子核保持在一起的有效力。这种力源于夸克和胶子（核子的组成部分）之间的基本相互作用，由量子色动力学方程描述。然而，由于这些方程不能直接求解，因此使用简化模型描述核相互作用，这些模型在典型的核子间距离下受到很好的约束，但在较短的距离下则没有。这限制了我们描述高密度核物质（例如中子星核心中的核物质）的能力。在这里，我们使用高能量的电子散射测量，隔离核子对在短距离，高动量的配置，-，访问一个运动学制度，以前没有被实验探索，对应于400兆电子伏特perc（c，在真空中的光速）以上的对之间的相对动量。随着两个核子之间的相对动量增加，它们的分离从而减少，我们观察到从自旋相关的张量力到主要是自旋无关的标量力的转变。这些结果表明，使用这样的测量研究在短距离的核相互作用的有用性，也支持使用点样核子模型与两个和三体有效的相互作用来描述核系统的密度高达几倍高于中心密度的核。
The strong nuclear interaction between nucleons (protons and neutrons) is the effective force that holds the atomic nucleus together. This force stems from fundamental interactions between quarks and gluons (the constituents of nucleons) that are described by the equations of quantum chromodynamics. However, as these equations cannot be solved directly, nuclear interactions are described using simplified models, which are well constrained at typical inter-nucleon distances, , , –but not at shorter distances. This limits our ability to describe high-density nuclear matter such as that in the cores of neutron stars. Here we use high-energy electron scattering measurements that isolate nucleon pairs in short-distance, high-momentum configurations, –, accessing a kinematical regime that has not been previously explored by experiments, corresponding to relative momenta between the pair above 400 megaelectronvolts perc(c, speed of light in vacuum). As the relative momentum between two nucleons increases and their separation thereby decreases, we observe a transition from a spin-dependent tensor force to a predominantly spin-independent scalar force. These results demonstrate the usefulness of using such measurements to study the nuclear interaction at short distances and also support the use of point-like nucleon models with two- and three-body effective interactions to describe nuclear systems up to densities several times higher than the central density of the nucleus.