Searches for Physics Beyond the Standard Model and Commissioning of the Level-1 Trigger Hardware in ATLAS

对物质最小成分的理论描述，即所谓的粒子物理学标准模型（SM），与过去几十年来获得的大量实验结果具有惊人的精确性。尽管达成了这一协议，但仍有许多问题是SM无法回答的。为什么我们会观察到三族粒子，为什么它们有它们的质量？这些都是存在的粒子吗？或者还有更多尚未被发现的粒子类型，例如，可以解释在天文观测中试图解释星系运动时似乎缺失的质量？由于我们到目前为止还没有看到它们，因此产生这样的粒子必须比我们迄今为止在粒子对撞机中所能达到的能量更多。解决这些问题的下一代设备是位于瑞士日内瓦的欧洲核子研究中心实验室的27公里长的粒子加速器LHC（大型强子对撞机）。在这里，能量比以往任何时候都高出七倍的碰撞将在两个多用途实验中记录下来，其中一个是ATLAS。ATLAS是有史以来最大的物理实验之一。它长约40米，高约20米，重约7000吨。在2007年秋季的第一次碰撞之前，仍有许多工作要做，以便将实验装置安装在地下洞穴中。实验的一个重要部分是触发系统，它必须决定每秒4000万次光束交叉中的哪些应该保留以供以后分析。由于每秒只能保持大约100个这样的交叉点，因此需要非常快速的机制来拾取ATLAS物理学家实现目标所需的数据。我提出的项目是一个组合的构建和调试ATLAS的触发系统，并在实验获得的数据中寻找新的现象。这两个主题是密切相关的，因为每个物理过程都需要仔细研究，以确保触发系统能够捕获泄露其存在的签名。当然，对于目前还不为人知的现象，这会带来很大的问题，这些问题可以通过关注大多数已提出的新模型所共有的性质来克服。我对粒子物理学中与物理学其他领域有直接联系的方面特别感兴趣。例如，引力的性质可能在LHC的粒子过程中表现出来，揭示了引力量子描述之后的长期思想。可能会发现新的粒子，可以解释解释星系运动所需的缺失或“黑暗”质量。有些东西可能需要数年的数据才能发现，然而，由于LHC的能量比以前的对撞机高得多，其他东西可能在运行开始后几个月才能发现。因此，这是一个理想的时间开始我上面所描述的项目。我们完全可以期待LHC实验的发现将永远改变我们对自然的理解，而不仅仅是它的亚原子部分。

The theoretical description of the smallest constituents of matter, the so-called Standard Model (SM) of particle physics, agrees with remarkable precision with the multitude of experimental results obtained over the last decades. In spite of this agreement many questions remain that the SM is not able to answer. Why do we observe three families of particles, and why do they have the masses they have? Are these all the particles that exist, or are there more as yet undetected particle types, that could for example explain the mass that seems to be missing when trying to explain the motion of galaxies in astronomical observations? As we have not seen them so far, such particles must need more energy to be produced than we have been able to achieve in our particle colliders so far. The next generation apparatus to attack these questions is the 27km long particle accelerator LHC (Large Hadron Collider) at the CERN laboratory in Geneva, Switzerland. Here collisions of up to seven times higher in energy than ever achieved before will be recorded in two multipurpose experiments, one of which is ATLAS. ATLAS is one of the largest physics experiments ever built. It will be approximately 40m long, 20m high and weight about 7000 tons. Until the first collisions in autumn 2007 much work still needs to be done to install the experiment in its underground cavern. An important part of the experiment is the trigger system, which has to decide which of the 40 million beam crossings per second should be kept for later analysis. As only about 100 such crossings per second can be kept, very fast mechanisms are needed to pick the data the ATLAS physicists needs to achieve their goals. The project I am proposing is a combination of constructing and commissioning the trigger system of ATLAS, and the search for new phenomena in the data aquired by the experiment. Both subjects are closely related, as every physics process needs to be studied carefully to make sure that the trigger system is able to capture the signatures that give away its presence. For as yet unknown phenomena this poses terrific problems, of course, which can be overcome by focussing on properties that are shared among most of the new models that have been proposed. I am particularely interested in aspects of paricle physics that have a direct connection to other fields of physics. For example the properies of the gravitational force may manifest themselves in particle processes at the LHC, revealing the long thought after quantum decription of gravity. New particles may be discovered that could explain the missing or 'dark' mass that is needed to explain the motion of galaxies. Some things might take years of data taking to discover, however, due to the much higher energy of the LHC compared to previous colliders, others may be discovered only months after operation starts. This is therefore an ideal time to start the project I have described above. We can fully expect that the findings of the LHC experiments will forever change our understanding of nature, and not only its subatomic part at that.