The Physics of the Dark Photon
The Physics of the Dark Photon
复制标题
DOI：
10.1007/978-3-030-62519-1
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
M. Fabbrichesi;E. Gabrielli;G. Lanfranchi
中科院分区：
文献类型：
--
作者：
M. Fabbrichesi;E. Gabrielli;G. Lanfranchi
标准模型之外的新粒子一直被认为至少在一些与普通粒子相同的规范相互作用下带电。尽管这一假设推动了过去50年的理论推测和实验研究，但它也越来越受到所有这些研究的负面结果的挑战，以及未能发现任何这些假设的新粒子的挫折感。随着沿着这些线取得突破的希望沿着减弱，人们对暗区的兴趣正在增加--暗是因为在标准模型规范群下不带电--也许没有看到新粒子仅仅是因为它们不通过标准模型规范相互作用相互作用。暗区可以是简单的，也可以是具有许多状态的复杂结构，其中一些状态可能是暗物质的候选者。如果暗区和可见区只在引力作用下相互作用--这是它们无法避免的--那么在实验室中观察到暗区粒子的希望就很小了。暗物质也存在类似的问题：尽管它的存在是由引力物理学激发的，但它主要是通过其假定的弱相互作用来搜索的，就像在对弱相互作用的大质量粒子的直接和间接探测搜索中一样。出于同样的原因，我们必须寄希望于这样一种假设，即暗区和普通区也通过一个门户（目前的术语）相互作用，也就是说，通过一个灰黄色的微光，以一种尽管微弱但（至少在原则上）在实验上可以达到的方式相互作用。门户可以采取各种形式，可以根据其运营商的类型和维度进行分类。最好的动机和最研究的情况下，包含相关的运营商采取不同的形式取决于自旋的调解人：矢量（自旋1），中微子（自旋1/2），希格斯（标量）和轴子（伪标量）。在这些可能的入口中，矢量入口是由于一个暗的和一个可见的阿贝尔规范玻色子之间的动力学混合而发生相互作用的入口（非阿贝尔规范玻色子不混合）。可见光子被认为是电磁学中的U介子规范群的玻色子--或者在电弱破缺标度以上的超荷的玻色子--而暗光子则被认为是额外的U介子对称性的玻色子。v
New Particles Beyond the Standard Model have always been thought to be charged under at least some of the same gauge interactions of ordinary particles. Although this assumption has driven the theoretical speculations, as well as the experimental searches of the last 50 years, it has also been increasingly challenged by the negative results of all these searches—and the mounting frustration for the failure to discover any of these hypothetical new particles. As the hope of a breakthrough along these lines is waning, interest in a dark sector—dark because not charged under the Standard Model gauge groups—is growing: Maybe no new particles have been seen simply because they do not interact through the Standard Model gauge interactions. The dark sector can be simple or have a complex structure with many states—some of which can be dark matter candidates. If the dark and the visible sectors were to interact only gravitationally—which they cannot avoid—there would be little hope of observing in the laboratory particles belonging to the dark sector. A similar problem exists for dark matter: Although its presence is motivated by gravitational physics, it is searched mostly through its putative weak interactions—as in the direct-and indirect-detection searches of a weakly interacting massive particle. For the same reason, we must pin our hopes on assuming that dark and ordinary sectors also interact through a portal—as the current terminology has it—that is, through a sallow glimmer, in a manner that, though feeble, is (at least in principle) experimentally accessible. The portal may take various forms that can be classified by the type and dimension of its operators. The best motivated and most studied cases contain relevant operators taking different forms depending on the spin of the mediator: Vector (spin 1), Neutrino (spin 1/2), Higgs (scalar) and Axion (pseudo-scalar). Among these possible portals, the vector portal is the one where the interaction takes place because of the kinetic mixing between one dark and one visible Abelian gauge boson (nonAbelian gauge bosons do not mix). The visible photon is taken to be the boson of the Uð1Þ gauge group of electromagnetism—or, above the electroweak symmetry-breaking scale, of the hyper-charge—while the dark photon comes to be identified as the boson of an extra Uð1Þ symmetry. v