Professor debates a matter of mass

An IU professor is involved in a controversy about physicists' continuing search for the Higgs boson, a particle that explains why matter has mass.\nThe Higgs boson is the last undetected particle whose existence is predicted by the Standard Model of particle physics, which has correctly described all experimental data on the structure and interactions of matter in the universe. \nAccording to the Standard Model, the Higgs boson is the reason all particles in the model have any mass. Without the Higgs boson, the particles would weigh nothing.\nGail Hanson, a distinguished professor of physics, has been involved with the European Laboratory for Particle Physics since the early 1990s. In 1995 she became part of OPAL, one of four research groups that would collect and test data to find evidence of the Higgs boson. Using the Large Electron Positron collider, or LEP accelerator, the scientists conducted searches by crashing atomic particles together at high speeds.\n"The Higgs boson is related to the electron weak force, a combination of the electromagnetic and weak force," Hanson said. "The weak force is what most think of as being responsible for radioactive decays and also responsible for many ordinary decays of particles. The electron weak theory requires there to be a particle called Higgs boson. It's the one missing ingredient in the model everyone accepts."\nThe Standard Model says particles receive their mass through a kind of friction with a field of energy, called the Higgs field, permeating all of space. The field cannot be detected directly, but the particle called the Higgs boson can be shaken loose from the field by agitating it with violent particle collisions in accelerators.\nIn September, the physicists ended years of finding no signal of the Higgs boson when they detected a possible sighting. The breakthrough occurred just before the LEP accelerator, located in a tunnel on the Swiss-French border, was supposed to be shut down and dismantled so a new particle collider could be built.\n"In physics, this is what you live for," Hanson said. "We were just about to finish running all the experiments and suddenly, at the very end, wow."\nAlthough these findings were not conclusive, the physicists involved in the project used the information to convince the laboratory to keep LEP running for another month. At the end of that period of time, in November, two more of the four experiment groups found events compatible with a Higgs boson.\n"We still don't have enough significant evidence to call it a discovery, even when you take all four events as evidence," Hanson said. "We asked for another six months of running LEP in 2001 so we could establish that this is a discovery. That was denied."\nOn the official European Laboratory for Particle Physics Web site, Director-General Luciano Maiani announced that LEP had been switched off for the last time Nov. 2. In a press release, the laboratory management announced it decided not to continue LEP because it felt the discovery did not merit running LEP in 2001 and that keeping the accelerator running would delay construction of the new, faster particle collider, which is set to go in the same tunnel LEP now occupies.\nAccording to the New York Times, Maiani said he decided keeping LEP running would be too great a gamble for the laboratory. Physicists working on it had asked for a year-long extension and modifications that would boost its energy slightly as opposed to delaying the research to build the new, faster LEP.\n"After several nights with difficult sleeping, we came to a decision," Maiani told the New York Times. "We did the best that we could. We believed that it was a decision based on the scientific case."\nWhen the IDS attempted to contact Maini, a representative said he was not granting any further interviews on the subject at this time.\nHanson said the scientists working on the LEP experiments felt press releases from the laboratory did not give any recognition to the possible discovery.\n"It's embarrassing if you think you've done something major and the official committee says you didn't," Hanson said. "You wait, you call up your friends. Especially if they have Nobel Prizes."\nThe laboratory's council will vote Dec. 15 on whether to dismantle LEP. Hanson said an end to LEP means the laboratory will most likely give up the Higgs boson discovery to Fermi National Accelerator Laboratory, or Fermilab, a Chicago-based lab conducting similar experiments. \nHanson said the discovery of the Higgs boson could be delayed until about 2007 if the laboratory scientists are forced to wait until the new accelerator is built and running properly.\n"It's a really stupid decision," she said. "I think they are going to be embarrassed by having to take it back." \nAt a lecture Hanson conducted for faculty, she said a meeting of the European Laboratory for Particle Physics scheduled for Friday could mean it might overturn the decision.\nDavid Rust, senior scientist in the physics department, was also involved in collecting data in the laboratory's search for the Higgs boson.\n"I think it's a good idea to keep (LEP) going for the next several months," Rust said. "We have a really good chance of being able to confirm the discovery"