arXiv 2103.108402021-03nucl-exnucl-th

中子电荷半径的测量及其组分的作用

Measurement of the neutron charge radius and the role of its constituents

H. Atac, M. Constantinou, Z. -E. Meziani, M. Paolone, N. Sparveris

备注：: https://doi.org/10.1038/s41467-021-22028-z
发表信息：: Nature Commun. 12, 1759 (2021)
DOI：: 10.1038/s41467-021-22028-z

摘要：

中子是我们描绘可见宇宙的基石。尽管有中子零净电荷，但由于复杂的夸克-胶子动力学，带正电荷（上）和带负电荷（下）的夸克的不对称分布导致其平方电荷半径$\langle r_{\rm n}^2 \rangle$为负值。因此，中子电荷半径的精确测量成为揭示其结构的重要组成部分。在这里，我们报告了一种$\langle r_{\rm n}^2 \rangle$测量，该测量基于在低四动量转移平方$(Q^2)$下提取中子电形状因子$G_{\rm E}^{\rm n}$，并利用$N \rightarrow Δ$四极跃迁和中子电形状因子之间已知的联系。我们的结果，$\langle r_{\rm n}^2 \rangle = -0.110 \pm0.008~({\rm fm}^2)$，解决了长期悬而未决的差异，在$\langle r_{\rm n}^2 \rangle$确定。强核力的动力学可以通过中子组分分布的精确图像来观察，这些分布导致非零的$\langle r_{\rm n}^2 \rangle$值。

英文摘要：

The neutron is a cornerstone in our depiction of the visible universe. Despite the neutron zero-net electric charge, the asymmetric distribution of the positively- (up) and negatively-charged (down) quarks, a result of the complex quark-gluon dynamics, lead to a negative value for its squared charge radius, $\langle r_{\rm n}^2 \rangle$. The precise measurement of the neutron's charge radius thus emerges as an essential part of unraveling its structure. Here we report on a $\langle r_{\rm n}^2 \rangle$ measurement, based on the extraction of the neutron electric form factor, $G_{\rm E}^{\rm n}$, at low four-momentum transfer squared $(Q^2)$ by exploiting the long known connection between the $N \rightarrow Δ$ quadrupole transitions and the neutron electric form factor. Our result, $\langle r_{\rm n}^2 \rangle = -0.110 \pm0.008~({\rm fm}^2)$, addresses long standing unresolved discrepancies in the $\langle r_{\rm n}^2 \rangle$ determination. The dynamics of the strong nuclear force can be viewed through the precise picture of the neutron's constituent distributions that result into the non-zero $\langle r_{\rm n}^2 \rangle$ value.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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英文摘要：

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