Investigations in Proton-Proton Collisions at the Large Hadron Collider

The ATLAS experiment operates at the highest energy collider in the world, the Large Hadron Collider (LHC) at the CERN laboratory near Geneva, Switzerland. The high energy collisions allow probes of the smallest distance scales and the recreation of the environment of the early universe. The LHC is both a discovery and a precision machine probing the standard model. The greatest discovery (so far) at the LHC has been the detection of the Higgs boson and the detailed measurement of its properties. The Michigan State University high energy physics group has been a member of the ATLAS collaboration since 1994 and has participated in the construction of many of the detector’s components and electronic systems. They have been involved in many physics analyses, including measurements of the Higgs boson, and other standard model final states, as well as searches for physics beyond the standard model that may result in a fundamental understanding of many of the open questions remaining in our understanding of the universe. These include why there is more matter than anti-matter and why gravity is so weak compared to the other forces. In addition to the physics goals, multiple education and outreach activities that target schoolchildren of various ages as well as the general public are planned. The work proposed in this award will improve the precision of standard model measurements, particularly those relating to the Higgs boson, the Z boson, and top quark production, in addition to fully exploring the parameter space of possible new physics. The scientific analyses can be broadly grouped into five general categories: the search for new, heavy resonances; the study of Higgs boson production and decay; the precision differential cross-section measurements of high mass Drell-Yan; the physics of top quarks; and the study of strong interactions, especially jet production in association with bosons and heavy quarks. With this award, the Run-2 analyses will be completed and extended using the data from Run-3, and important detector upgrades will be carried out as needed for ATLAS to collect data in the high luminosity era. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.