By George Foulsham

When scientists at the newly constructed Large Hadron Collider (LHC) in Geneva sent beams of protons in opposite directions through the collider’s 17-mile circular chamber for the first time on September 10, it marked a milestone for the UCSB particle physics program.

Situated some 300 feet below the Earth’s surface and spanning the distance from Switzerland to France and back again, the LHC at the European Organization for Nuclear Research (CERN) is the world’s largest particle accelerator. A contingent of more than 40 faculty members, graduate students, postdoctoral researchers, engineers, technicians, and undergraduates from UCSB have worked for eight years to help construct the experimental apparatus. They are part of an international effort that is now embarking on a 15-year quest to try to answer fundamental questions about the universe.

Led by four members of its experimental high-energy physics faculty, UCSB’s team has played a key role in constructing one of four major experiments now in place — the Compact Muon Solenoid (CMS), a complex array of instruments for detecting subatomic particles. The device weighs more than 12,000 tons and is as tall as a four-story building. Professor Joseph Incandela has been in Switzerland for the past year, shepherding the CMS experiment as deputy physics coordinator. Shuttling back and forth between Santa Barbara and Switzerland have been professors Claudio Campagnari, Jeffrey Richman, and David Stuart.

UCSB’s initial role in the CMS experiment was to build part of the particle tracking system, which measures the paths of particles produced in the proton-proton collisions. By combining the information from all parts of the CMS detector, scientists can reconstruct an electronic image of what happens in each collision.

According to Incandela, UCSB delivered 2.5 million channels of particle detectors, which were meticulously constructed in cleanrooms in the university’s physics department. The detectors were of “extremely high quality,” Incandela said, noting a failure rate of only 0.02 percent. “Our group then helped assemble and test the detectors at CERN.”

CMS is a huge project involving thousands of scientists from all over the world. While many U.S. universities have contributed time and staff to CMS and other LHC experiments, UCSB has played a leading role in the construction of the detector’s tracking system. One-third of this enormous system was assembled and tested at UCSB.

With so many possibilities for discovery, the anticipation for the startup of this program has been enormous. “It’s great that the machine has turned on,” Campagnari said. “I don’t think we’re going to turn it on in September and make discoveries in October. But discoveries could start coming soon and could happen over many years.”

“This is a historic undertaking, and it is great to be part of it,” Incandela said. “We are working with some of the top particle physicists of our era to prepare for what we might see. The range of possibilities is broad, but the most incredible aspect of this program is that whatever we see will be very important to our understanding of the basic forces of nature.”