How a chemistry student became a particle physicist hunting for the universe’s missing pieces

Liron Barak says her path into particle physics began unexpectedly, when she was an undergraduate chemistry student and attended a summer lecture by Prof. Eilam Gross at the Weizmann Institute of Science. Gross spoke about the search for the Higgs particle and the ambitious future CERN accelerator, and Barak left determined to work in the field, even though the move from chemistry to physics was not obvious.

She later switched to physics for her master’s degree and is now a faculty member at the University of Tel Aviv, where she heads a research group in particle physics. Her team works on ATLAS, one of the two main detectors at the Large Hadron Collider, LHC, at CERN near Geneva. The collider speeds particle beams to near light speed and smashes them together, allowing scientists to study the debris for signs of new elementary particles.

Barak says the job is less about microscopes and more about data. The accelerator produces millions of collisions every second, and only a tiny fraction may contain clues to new physics. Her group develops machine-learning algorithms to find hidden patterns and unusual events that could indicate a new particle or an unobserved physical process.

She argues that the search matters because the Standard Model, while highly successful, still leaves major gaps. Neutrinos were once thought to have no mass, but experiments showed they do have a very small one, requiring extensions to the theory. Dark matter is an even bigger mystery, she says, since more than 80% of the universe’s matter appears to be invisible and the Standard Model has no particle to explain it. Barak says the hope is to add another chapter to the history of science by discovering phenomena beyond current knowledge.