What brings about this important difference in the mass of these "field" particles? This mass difference leads to much of the difference in how the forces are experienced in Nature. The difference is know technically as electroweak symmetry breaking. The Oregon group participates in the ATLAS experiment to investigate this question.
Four faculty, one research associate, and three graduate students are presently working on ATLAS. Since Oregon joined ATLAS early in 2006, the group has devoted its effort to the process of selection of interesting events generated by the collisions of high energy particles within the ATLAS detector. Many times more events are produced than can be recorded. A High Level Trigger provides an important step in this selection process. Oregon's interest here has been particularly related to selecting tau leptons. Tau leptons are the heaviest leptons, and in many theoretical models are particularly connected to possible evidences of new physics. Optimizing the trigger for their detection is therefore an important activity. Oregon has been working to use the inner tracker data to do this.
As the ATLAS detector collects data from collisions, and data analysis becomes possible, the Oregon group plans to explore the general theme of electroweak symmetry breaking described above through a few different physics studies. These include tau physics, heavy Z boson searches, and black hole production.