After completion of repairs and upgrades, the European Organization for Nuclear Research, or CERN, is rebooting its Geneva-based Large Hadron Collider, allowing physicists both across the globe and on UC Berkeley’s campus to once again be able to make use of the data it provides on established and undiscovered particles.
According to campus physics professor and LHC researcher Marjorie Shapiro, the LHC, which, as a result of new design upgrades, has the potential to reach energy levels it could not reach before, was closed in February 2013 so that design flaws could be rectified. While it was out of commission, UC researchers improved the functionality of detectors that capture the movements and emissions of high-energy particles.
One of the main instruments the researchers are involved with is the detector of the ATLAS experiment. UC scientists have been part of the experiment for more than 20 years — more than 10 years before the first data were even collected. These scientists are representatives of two of Berkeley’s major scientific forces: the campus physics department and the Lawrence Berkeley National Laboratory.
CERN conducts its experiments with two tools: accelerators, which speed up the protons to the velocity necessary to collide at immense energies, and detectors, which measure the data resulting from the the particles’ collision.
ATLAS, one of four detectors located in caverns on the LHC ring, records the energy, path and momentum of the particles resulting from proton collisions on magnetic strips. From there, the particles’ properties can be documented for researchers’ analysis.
Shapiro said there are three main frontiers open for exploration when the second run of the collider occurs. Scientists will be on the lookout for additional details regarding already discovered particles such as the Higgs boson, which was famously discovered with data from the LHC; the production of particles such as dark matter or supersymmetric particles, which were too heavy to create with the LHC until recently; and the possibility of unexpected discoveries.
“Truly, we’re looking for anything that looks strange to really explore,” Shapiro said. “(We) want to look at anything unexpected and ask, ‘Can I find out what is going on here?’ ”
Because each collision generates a large amount of data, researchers set up certain “triggers,” or specific experiments they want to record. According to Shapiro, teams of researchers working with the LHC have found that the “trigger” method proves difficult when designing ways to observe unexplored particles that were unobservable prior to the renovations, such as dark matter.
“It’s a little nerve-wracking, because (the renovations are) the last major increment in capability that we’ve got,” said UC Berkeley physics professor Bob Jacobsen in an email. “For the next years, this is the last big window to look through! So I really hope the view is interesting.”
Contact Kate Wolffe at [email protected].