Two Haverford alumni are involved in the most extensive physics experiment in history.

Hugh“Brig” Williams '66 and Stephon Alexander '93 are among the international scientists working on the Large Hadron Collider (LHC), the world's most powerful particle accelerator. The multi-billion-dollar LHC, which had its official test run on Sept. 10, 2008, was designed to provide clues to the universe's composition.

Buried in a tunnel deep beneath the French-Swiss border, the LHC will produce collisions of protons traveling at nearly the speed of light. As the protons collide, the LHC's massive detectors will search for evidence of dark matter, hidden dimensions of space and time, and the“Higgs boson” or“God” particle, which is believed to give mass to all other particles in the universe. Although some fear that the proton collisions could create tiny black holes with gravity strong enough to swallow the Earth, most scientists anticipate that the LHC will answer some of their most pressing questions about the universe's origins.

Brig Williams, a professor at the University of Pennsylvania, is part of a group that has been developing one portion of the project for 14 years. The ATLAS detector will allow scientists to see particles produced by the collision of two high-energy protons and will provide images of the 40 million proton collisions that occur every second within the Collider.

Williams was in the control room in Switzerland the day scientists tested the LHC by running a continuous beam through the entire accelerator to make sure it was operational. The test was deemed a success. “There was a tremendous amount of excitement,” Williams reports,“and the control room was absolutely packed—initially they were going to restrict the Control Room to ‘operators only' but they gave up trying to keep people out.” He will return to Switzerland in October and December, as the Penn team refines the operational stability of the detector and, once collisions occur, improve understanding of how the detector performs with a large number of particles at once.

Stephon Alexander, associate professor of physics at Haverford, has developed a new theory that unifies the weak nuclear reaction (the second weakest force in nature) with Einstein's theory of space-time, and is working on a way to experimentally confirm this unification at the LHC.“One of the most important questions that the LHC will try to answer is the origin of mass,” he says.“Also, the energy that will be accessed will allow us to understand how and if the forces [both gravity and weak force] are unified.”

-Brenna McBride