Extension to the build project for the Mu3e MuPix Pixel Tracker

Mu3e实验将研究大量的μ子衰变。为此，实验背后的团队正在建造一个探测器，可以以前所未有的精度测量这些衰变中产生的子粒子。实验将寻找一种非常特殊的衰变类型，在这种衰变中，反μ子衰变为2个正电子和1个电子。关键是，在这个过程中，反μ子失去了它的"味道"，变成了正电子。虽然其他粒子如夸克和中微子已知会这样做，但这种味道的变化从未在带电轻子（电子，μ子或τ子）中观察到。如果粒子物理学的成熟标准模型（SM）是完整的故事，则不应该观察到涉及违反带电轻子味守恒的过程。然而，粒子物理学家希望解决物理学中的一些大问题，例如为什么在我们的宇宙中物质比反物质占主导地位，需要超越标准模型的新模型。已经提出了过多的这种模式，但仍然缺乏实质性证据来证实其中任何一种模式。到目前为止，以前的实验已经排除了每1，000，000，000，000（1E12）次衰变中发生一次以上涉及带电轻子味破坏的μ子衰变。Mu3e实验的灵敏度将提高10，000倍，可能会在这个已经令人印象深刻的结果上增加4个零;或者-更好的是-找到衰变过程的证据，并找到新物理学的直接证据。粒子物理学家试图回答的另一个关键问题是了解神秘暗物质的性质。暗物质的存在从天文观测中得到了有力的证实，但其性质仍然未知。Mu3e实验的独特能力可以非常精确地研究大量μ子的衰变产物，也允许将建造和操作探测器的团队成员搜索假设的暗光子，这些光子可能提供我们所知道的物质粒子与暗物质粒子隐藏世界之间的联系。

The Mu3e experiment will study a very large numbers of muon decays. For this the team behind the experiment is building a detector that can measure with unprecedented accuracy the daughter particles produced in these decays. The experiment will look for a very specific type of decay in which an anti-muon decays to 2 positrons and an electron. Crucially, in this a process the anti-muon loses its "flavour" to become a positron. Although other particles such as quarks and neutrinos are known to do this, such a change of flavour has never been observed for the charged leptons (electrons, muons or taus). If the well-established standard model (SM) of particle physics is the complete story, processes involving the violation of the conservation of charged lepton flavour should not be observed. However, particle physicists expect that to address some big questions in physics, such as why in our universe matter dominates over antimatter, new models going beyond the standard model are needed. A plethora of such model have been formulated but substantive evidence to corroborate any of these remains absent. To date, previous experiments have excluded that muon decays involving charged lepton flavour violation occur more than once in every 1,000,000,000,000 (1E12) decays. The Mu3e experiment will be more sensitive by a factor 10,000, potentially adding 4 zeros to this already impressive result; or - much better - finding evidence of the sought after decay process and with that, direct evidence of new physics. Another key question particle physicist are trying to answer is to understand the nature of the mysterious dark matter. The existence of dark matter is strongly established from astronomical observations, but its nature remains unknown. The unique capabilities of the Mu3e experiment to study with great precision the decays product of a very large number of muons, also allows the members of the team that will build and operate the detector to search for hypothetical dark photons that may provide a link between the matter particles we know and a hidden world of dark matter particles.