The ATLAS Experiment

at the Kirchhoff-Institute for Physics

ATLAS is one out of four large experiments at the Large-Hadron-Collider (LHC) at CERN in Geneva. It is dedicated to a comprehensive study of very high-energy proton-proton collisions at the terascale. A primary goal is the search for new phenomena beyond the horizons of the known standard model of particle physics. Such phenomena will crucial for the understanding of the development of the early universe at times as small as 10-12 seconds after the Big Bang.

The Heidelberg group has been one of the ATLAS founding members in 1992. Before, the group has been a member of the RD27 collaboration which developed concepts for triggering in the high rate LHC environment. Together wih 5 other groups from England, Germany and Sweden the group has designed and built the ATLAS level-1 calorimeter trigger. The Heidelberg contribution in this project has been the design and the construction of the Calorimeter Trigger Preprocessor (PPr) which digitises and processes 8000 channels of calorimetric energy measurements 40 million times per second. The PPr is a crucial component for ATLAS operation.

In the analysis of physics processes the group dedicates its efforts to both precision measurement of the Standard Model and search for new physics beyond that model. Current work-in-progress includes tests of Quantum Chromodynamics (QCD) at extremely high momentum transfers, investigation of missing transverse momentum from undetectable particles and the search for mini black-holes. Additionally the group works on calibration of hadronic jets which are used for physics analysis.

The ATLAS project has been a strong driver for the foundation of the Heidelberg ASIC laboratory for microelectronics hosted by the KIP. A graduate research group 'New Symmetries and Extra Dimensions' is established within the KIP ATLAS group with doctoral projects supported by scholarships of a Baden-Württemberg graduate research grant. At the department level the group contributes to the Graduate School of Fundamental Physics and to the DFG Research Training Group 'HighRR – High Rate and High Resolution Detectors for Nuclear and Particle Physics'. On the national scale the Heidelberg group is a member of the BMBF Research Unit FSP103 'ATLAS' and of the Helmholtz-Alliance 'Physics at the Terascale'.

The ATLAS Detector