U faculty weigh in on LHC shut down

Although there wonâÄôt be any proton collisions at the Large Hadron Collider in Geneva for the next several months, University physics professor Roger Rusack said there is work to be done before it reopens, likely in March or April of 2009. Last Friday, a helium leak, likely the result of faulty wiring, caused the LHC to shut down. In order to make repairs, the collider must be heated to room temperature âÄî about 560 degrees Fahrenheit above the near absolute zero temperatures the collider operates at. The warm up and cool down alone will take about two months and will be followed by a scheduled shutdown for winter, when heightened electricity costs prevent the collider from running. Rusack, whoâÄôs been working on the LHC since 1993, said he had a lot of confidence in CERN, the European Organization for Nuclear Research, to deal with the problem and prevent similar issues from happening in the future. âÄúIâÄôm quite sure that theyâÄôll check and make sure that each one of these connections is good,âÄù he said. Kenneth Heller, a University physics professor, said an electrical problem with the LHC didnâÄôt come as a surprise to anybody. âÄúItâÄôs a big, complicated gadget,âÄù he said, and added that people have actually been amazed at how smoothly it had been operating up to that point. Rusack said Ph.D. students whose theses depend on data from LHC proton collisions will be most impacted by the shutdown. University physics professor Yuichi Kubota said his graduate student is in Geneva now, where he had hoped to âÄúwitness the historical moment of the first colliding beam.âÄù Now heâÄôll have to wait for several more months. Kubota added that although the delay is a bit of a drag, there is maintenance and testing that can be done on the Compact Muon Solenoid while the collider is shut down. Jason Haupt, a graduate student working with Rusack, said the shutdown was âÄúkind of upsetting, but I knew it could happen.âÄù Haupt said he has been working for the past several years on calibrating the electromagnetic calorimeter (ECAL), a type of particle detector that uses lead crystals. This detector is a component of the 14,000-ton Compact Muon Solenoid, one of the colliderâÄôs two main detectors. Rusack, who is in Geneva this week, will become the project manager for ECAL in January. That means heâÄôll be responsible for the 90-ton crystal detector, which is designed to detect photons and electrons with high precision. As project manager, Rusack will be working with 200 physicists from all over the world. Collaboration is a major part of the LHC project, and Kubota said it has been a big accomplishment for the physicists to get used to working together. The detector that Rusack is involved with is just one of many components essential to achieving the goals of the Large Hadron Collider. Kenneth Heller, University physics professor, said the primary goal of the LHC is to understand the origin of mass. The current theory requires a particle called the HiggâÄôs boson, which the device is designed to detect. âÄúEither [the particle] will be found, and we will slap ourselves on the collective back and say âÄòAh, we understand physics, even at this level,âÄô or it wonâÄôt be found and we would get very puzzled,âÄù he said. Things like extra dimensions and miniature black holes could also be explored by the LHC, said Heller. Joseph Kapusta, a theoretical physicist and University physics professor, is working with a team that plans to use heavy nuclei collisions to recreate the matter that resulted from the big bang. Kapusta, who has published a paper on accelerator disaster scenarios, said the chances that LHC experiments will cause disaster are much smaller than the probability that an asteroid will hit the Earth and destroy half the life on the planet âÄî something that happens every 60 million to 100 million years.