Physicists Celebrate Big Day in the Cosmos
BU students and researchers witness Large Hadron Collider success| From BU Today | By Art Jahnke
CAS physics prof Lawrence Sulak and his class watch a live feed from the Large Hadron Collider March 30. Photo by Kalman Zabarsky
After more than 25 years — at least 10 in planning and 16 in construction — plus one failed attempt, the world’s most powerful particle accelerator hit pay dirt on March 30 when two super-energized particle beams collided, releasing an extremely short-lived plasma that scientists believe approximates the origin of all matter.
“The hope is to discover what happened in the first few instances after the big bang,” says Lawrence Sulak, David M. Myers Distinguished Professor of Physics and one of several BU researchers and students who work on the Large Hadron Collider. “If we can re-create what the reactions were in the early universe, we can extrapolate to understand more about our universe today.”
The collider, which straddles the Franco-Swiss border near Geneva, is a 16-mile underground vacuum tube lined with 4,000 of the world’s most powerful superconducting magnets. Operating at a temperature of two degrees above absolute zero, particle beams are pulled around the 16-mile loop more than a billion times, until they approach the speed of light. Their collisions, which were occurring at about 100 times a second, release fundamental particles such as quarks and gluons. The actions of those particles are recorded, and that information is sent instantly to hundreds of the world’s largest supercomputers.
Such evidence, says Sulak, could help resolve theoretical disputes about the structure and evolution of the universe that have been ongoing for decades.
BU researchers helped develop the leads that carry 4,000 amps of current through the collider’s magnets. On March 23 his cosmology class watched a live broadcast of exuberant physicists at CERN (Conseil Européen pour la Recherche Nucléaire), the research facility, also called the European Organization for Nuclear Research, that houses the collider.
The goal of the start-up, he says, is to produce new or rare particles, e.g., the top quark, and to study their instantaneous decay into “daughter particles.”
The collider’s success, celebrated by physicists throughout the earthly cosmos, came a year and half after its first attempt. In September 2008, researchers halted the initial effort when magnets began to malfunction.
“It was a huge mess,” recalls Sulak. “You had one tunnel filled with helium gas and huge blocks of air. The magnets couldn’t survive that accident.”
In the LHC Experimenter Building at CERN, Max David Yellen (CAS’11) (from left), Chelsea Bartram (CAS’11), Michael Allan Lloyd (CAS’11), Michael Hedges (CAS’11), Andrea Jayne Welsh (CAS’11), Cheung Yee Lam Elim (CAS’11), and Ashley Rubinstein (CAS’11), students in the Geneva study-abroad program, in front of TV monitors in the CMS control rooms.
The historic success was also witnessed by seven BU juniors participating in a new study-abroad program. All physics majors, they are working on site, each with a BU scientist.
Speaking by phone from CERN, Michael Hedges (CAS’11) said the milestone reminded him of videotapes he’s seen of celebrations in the control room at NASA.
“After what happened in 2008, there was obviously some fear that something would go wrong,” said Hedges, whose work this semester is a comparison of the accuracy of researchers’ predictions versus what actually happens. “There was a very careful and slow process to make sure we could put forth the collisions without damaging the machine. We were running at half of the energy it is capable of.”
Sulak says the CERN team will proceed with caution.
“We are taking it slowly,” says Sulak. “We are operating at seven TeV (trillion electron volts). We will run until the end of 2011, when we will turn it off for a year and half and replace all the splices between magnets, then three years from now the accelerator physicists will crank it up to 14 TeV.”