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

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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.