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ATLAS is an experiment operating at the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. The LHC is the world's highest energy accelerator, and will be the premier experimental HEP collider facility for many years to come.

The foremost question of HEP is the source of so-called "electroweak symmetry breaking" (EWSB), related to the issue of the origin of mass. The Standard Model (SM) of particle physics postulates the existence of the Higgs boson to solve this issue. In July 2012, ATLAS and CMS, the two large LHC experiments, announced the discovery of a new particle with properties very much like those predicted for the Higgs boson. As a result, the 2013 Nobel Prize in Physics was awarded to Peter Higgs and Francois Englert, two of the theorists who, in 1964, proposed this solution for EWSB. Whether this new particle behaves precisely as expected for the Higgs boson, or whether there are discrepancies that could point the way to new physics, is an area of intensive study. In addition, even with the Higgs boson, there are many questions that cannot be answered by the SM. Many other scenarios (eg. supersymmetry, technicolor, even the existence of extra spacetime dimensions) have been proposed. The LHC and ATLAS are designed to explore in detail physics at the TeV scale, where it is widely expected that signs of new physics should be discoverable.

The Columbia ATLAS group has played a number of roles in the experiment, including leading the development (from design through installation and commissioning) of the readout electronics of the liquid argon calorimeters, participating in the commissioning of the pixel tracking detector, a variety of software and data acquisition developments, and studies of the ATLAS detector performance and physics potential. We have been heavily involved in physics analysis with the enormous data samples recorded at proton-proton center-of-mass energies of 7 TeV in 2011 and 8 TeV in 2012. In addition, we are performing R&D aimed at developing the next generation of readout electronics for the ATLAS calorimeter system.

The LHC began operations again in 2015, with an increased center-of-mass energy of 13 TeV, greatly extending the potential to discover new physics beyond the SM. The current run will extend until the end of 2018.