Bell Lecture

Exploring the energy frontier with the ATLAS experiment at the Large Hadron Collider

Michel Lefebvre

Department of Physics and Astronomy
University of Victoria

The recent discovery of a new particle opens up a new window in our exploration of the fundamental constituents of matter and the interactions between them. To date, the Standard Model of particle physics is extremely successful and accounts for all measured subatomic phenomena. However the postulated Higgs mechanism, from which all particles acquire mass, remains to be verified experimentally. Is the new particle the predicted Standard Model Higgs boson? Many other questions are so far left unanswered. Research at the energy frontier is being carried out at the Large Hadron Collider (LHC), operating at CERN near Geneva since 2010. The LHC currently provides proton-proton collisions at a centre of mass energy of 8 TeV, allowing the exploration of distance scales smaller than 10^-19 m. The ATLAS detector is successfully recording the products of these collisions; it will be introduced with an emphasis on Canadian contributions. The ATLAS experiment has collected a large data set in 2012, and features Standard Model physics measurements and a rich programme of searches for new physics phenomena. The discovery of a new particle and other important results will be presented. The future increase in energy and intensity at the LHC, and the associated ATLAS plans, will also be discussed. These are exciting times indeed for particle physics!