Teachers and Students This is the dawn of an exciting age of new discovery in the study of elementary particles and their interactions. The current theoretical framework of the fundamental nature of matter, known as the Standard Model, explains much, but leaves many unanswered questions. What is dark matter? What happened to antimatter? Are there extra dimensions of spacetime? Are there new symmetries of nature? Are there new, as yet unobserved, forces? What is responsible for mass? The Large Hadron Collider (LHC), a huge scientific instrument at CERN, provides the highest-energy particle collisions produced in a laboratory to six experiments that hold the potential to answer these questions. |
Event of the Week, 05/03/2012: Photon scores a conversion in ATLAS
A candidate for the predicted decay of the Higgs is into two photons. This is a slice of such an event. As a neutral particle, the photon leaves no track unless it "converts" into an electron and a positron, as happened in this event. For clarity though, a line has been added from the central vertex of the event (magenta dot) at 4 o'clock to show the path of the photon. This line stops where photon converts (at the brown dot) to an electron and a positron, seen as red and blue tracks, respectively. The actual signals in ATLAS are represented by the small red and blue dots in the tracker and the thick yellow energy deposit in the electromagentic calorimeter. The other lines and thick dots are all reconstructions from the data they represent.
Credit: ATLAS Experiment © 2011 CERN
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