Electric dipole moments of atoms, molecules, nuclei, and particles
Electric dipole moments of atoms, molecules, nuclei, and particles
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DOI：
10.1103/revmodphys.91.015001
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发表时间：
2019-01-04
影响因子：
44.1
通讯作者：
Singh, J. T.
中科院分区：
文献类型：
--
作者：
Chupp, T. E.;Fierlinger, P.;Singh, J. T.
粒子或系统的永久电偶极矩(EDM)是电荷沿其角动量轴的分离，是T破坏的直接信号，并且假设CPT对称，则CP破坏。60多年来，人们一直在研究EDMS，首先是作为宇称对称性破坏的信号，然后是CP破坏的信号，这将阐明它在性质和理论上的作用。当代的动机包括CP破坏在解释宇宙物质-反物质不对称性中所起的作用，以及对新物理的探索。在各种系统上的实验已经变得越来越敏感，但只提供了EDM的上限，而几个尺度上的理论对于解释这些上限至关重要。核理论提供了从标准模型和超标准模型物理到可观察到的电子能谱的联系，原子和分子理论揭示了在这些系统中CP破坏是如何明显的。强子系统中的EDM结果要求标准模型的(Theta)的QCD参数必须非常小，这可以用轴子的存在来解释，轴子也是一个候选的暗物质粒子。关于电弱重子发生的理论结果表明，需要新的物理学来解释物质在宇宙中的主导地位。实验和理论工作继续扩大，新的想法和新的问题，这篇综述提供了理论动机和解释的广泛概述，以及关于实验技术、实验和前景的细节。其目的是在这一激动人心的领域向前发展时提供具体细节和背景。
A permanent electric dipole moment (EDM) of a particle or system is a separation of charge along its angular momentum axis and is a direct signal of T violation and, assuming CPT symmetry, CP violation. For over 60 years EDMs have been studied, first as a signal of a parity-symmetry violation and then as a signal of CP violation that would clarify its role in nature and in theory. Contemporary motivations include the role that CP violation plays in explaining the cosmological matter-antimatter asymmetry and the search for new physics. Experiments on a variety of systems have become evermore sensitive, but provide only upper limits on EDMs, and theory at several scales is crucial to interpret these limits. Nuclear theory provides connections from standard-model and beyond-standard-model physics to the observable EDMs, and atomic and molecular theory reveal how CP violation is manifest in these systems. EDM results in hadronic systems require that the standard-model QCD parameter of (theta) over bar must be exceptionally small, which could be explained by the existence of axions, also a candidate dark-matter particle. Theoretical results on electroweak baryogenesis show that new physics is needed to explain the dominance of matter in the Universe. Experimental and theoretical efforts continue to expand with new ideas and new questions, and this review provides a broad overview of theoretical motivations and interpretations as well as details about experimental techniques, experiments, and prospects. The intent is to provide specifics and context as this exciting field moves forward.