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arXiv 2003.02231hep-ph
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强平面波场中电子正电子湮没成两个光子

Electron-positron annihilation into two photons in an intense plane-wave field

S. Bragin, A. Di Piazza

摘要:

本文采用光锥量子化方法,在严格考虑平面波效应的情况下,分析研究了在任意形状的强经典平面波作用下,电子正电子湮没湮灭为两个光子的过程.本文介绍了平面波背景场中二阶2对2散射过程的一般描述,指出了考虑碰撞粒子局域化并利用波包实现局域化的必要性。我们在背景场中定义了一个局部截面,它概括了真空截面,虽然它不是直接的可观测的,但它允许在平面波和真空中的结果之间进行比较,而不依赖于入射波包的形状。在湮没过程中发现了两种可能的级联或两步通道,并找到了用“虚”积分表示两步和一步贡献的另一种方法.最后,计算了正负电子场与量子化光子场耦合到首级的总局域截面,排除了由两个最后光子的交换引起的两个前导级图之间的干涉,并以相对紧凑的形式表示。与由单个粒子引发的背景场中的过程相反,对湮灭为两个光子实际上也发生在真空中。我们的结果自然嵌入真空部分,并减少到真空的表达,在文献中已知的情况下,消失的激光场。

英文摘要:

The process of electron-positron annihilation into two photons in the presence of an intense classical plane wave of an arbitrary shape is investigated analytically by employing light-cone quantization and by taking into account the effects of the plane wave exactly. We introduce a general description of second-order 2-to-2 scattering processes in a plane-wave background field, indicating the necessity of considering the localization of the colliding particles and achieving that by means of wave packets. We define a local cross section in the background field, which generalizes the vacuum cross section and which, though not being directly an observable, allows for a comparison between the results in the plane wave and in vacuum without relying on the shape of the incoming wave packets. Two possible cascade or two-step channels have been identified in the annihilation process and an alternative way of representing the two-step and one-step contributions via a "virtuality" integral has been found. Finally, we compute the total local cross section to leading order in the coupling between the electron-positron field and the quantized photon field, excluding the interference between the two leading-order diagrams arising from the exchange of the two final photons, and express it in a relatively compact form. In contrast to processes in a background field initiated by a single particle, the pair annihilation into two photons, in fact, also occurs in vacuum. Our result naturally embeds the vacuum part and reduces to the vacuum expression, known in the literature, in the case of a vanishing laser field.

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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