Abstract

 In this review we discuss the status of the research for the three-body positronium negative ion (\(\hbox {Ps}^{-}\), \(e^{-}e^{+}e^{-}\)) and the four-body positronium molecule (\(\hbox {Ps}_{{2}}\), \(e^{-}e^{+}e^{-}e^{+}\)) from both theoretical and experimental points of view. Experimental results are included to compare with theoretical predictions. J. A. Wheeler, during the 1940s, proved that \(\hbox {Ps}^{-}\) has a stable bound state and he also speculated that larger systems such as \(\hbox {Ps}_{{2}}\) can exist. There have been several theoretical works starting from the 1940s about the properties of \(\hbox {Ps}^{-}\) and \(\hbox {Ps}_{{2}}\). However, experimental observation of such exotic systems proved to be challenging. Thus, \(\hbox {Ps}^{-}\) was first observed in 1981 and Ps\( _{2}\) was only seen in 2007. During recent decades, there have been major advances in determining the properties of the positronium negative ion and the positronium molecule. These studies shed light on the properties of such exotic systems and allow us to better understand and test the theory of quantum electrodynamics (QED).

Graphic abstract

中文翻译：

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正电子离子与分子的实验与理论研究综述

摘要

 在这篇综述中，我们讨论了三体正电子负离子（\(\hbox {Ps}^{-}\) , \(e^{-}e^{+}e^{-} \) ) 和四体正电子分子 ( \(\hbox {Ps}_{{2}}\) , \(e^{-}e^{+}e^{-}e^{+}\ ) ) 从理论和实验的角度来看。包括实验结果以与理论预测进行比较。JA Wheeler 在 1940 年代证明了\(\hbox {Ps}^{-}\)具有稳定的束缚态，他还推测更大的系统如\(\hbox {Ps}_{{2}}\ )可以存在。从 1940 年代开始，关于\(\hbox {Ps}^{-}\)和\(\hbox {Ps}_{{2}}\)。然而，对这种奇异系统的实验观察证明是具有挑战性的。因此，\(\hbox {Ps}^{-}\)于 1981 年首次被观察到，而 Ps \( _{2}\)仅在 2007 年才被发现。近几十年来，在确定正电子负离子和正电子分子。这些研究阐明了这种奇异系统的特性，并使我们能够更好地理解和测试量子电动力学 (QED) 理论。

图形摘要