Hunting for Higgs

MIT physics professor Steven Nahn, PhD ‘98, felt “guarded jubilation” on the morning of September 10, when a beam of protons completed the first 27-­kilometer trip around the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) in Switzerland. The huge particle accelerator could help scientists understand some of the biggest mysteries of the physical world.

Ultimately, the LHC will accelerate beams of subatomic particles in opposite directions and smash them into each other. These collisions will produce new particles, which Nahn and his group can detect and analyze by tracking their paths through the magnetic fields of the accelerator’s detectors. They hope that one such particle will be the Higgs boson, which is what many scientists believe endows some of the smallest units of matter with mass. Within three years, “we should be able to say definitively whether the Higgs model is correct or if there is something entirely new,” Nahn says.

In addition to setting the stage for the discovery of new particles, the high-energy collisions will enable scientists to study matter under extreme conditions. By late 2009, they will begin to study collisions between lead nuclei, potentially allowing them to simulate conditions in the universe one-millionth of a second after the Big Bang, says Gunther Roland, an MIT physics professor involved in the research.

Scientists hope to witness the first proton collisions by the end of 2008. “At the very beginning, it will be chaos,” says Nahn. “It will be great.”