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Massive Magnet Helps UCR Physicists

Down with Physics: Giant Compact Muon Solenoid Magnet Goes Underground at World's Largest Particle Physics Laboratory

UCR physicists to participate in the international experiment

(February 28, 2007)

RIVERSIDE, Calif.— Scientists of the US Compact Muon Solenoid (CMS) collaboration, which includes UC Riverside physicists, joined colleagues around the world in announcing today that the heaviest piece of the CMS particle detector has been lowered into its experimental cavern 100 meters underground.

A huge gantry crane is slowly lowering the CMS detector’s preassembled central section into place in the Large Hadron Collider accelerator at the world's largest particle physics laboratory, CERN, in Geneva, Switzerland. At 1,950 metric tons, the section, which contains the detector’s solenoid magnet, weighs as much as five jumbo jets and is 16 meters tall, 17 meters wide and 13 meters long. Its descent is expected to take about 10 hours.

“This is a challenging feat of engineering, as there are just 20 centimeters of leeway between the detector and the walls of the shaft,” said CERN physicist Austin Ball, technical coordinator of CMS. “The detector is suspended by four massive cables, each with 55 strands, and attached to a step-by-step hydraulic jacking system, with sophisticated monitoring and control to ensure the object does not sway or tilt.”

Robert Clare, John Ellison, J. William Gary, Gail Hanson, Owen Long, Benjamin Shen and Stephen Wimpenny — all faculty members in the department of physics and astronomy at UCR — belong to the US CMS collaboration and will participate in the CMS experiment. Clare, Gary and Hanson have been involved in the design of the experiment from the beginning.

Of the CMS collaboration’s approximately 1500 physicists, about one-third are U.S. scientists. The Department of Energy’s Fermi National Accelerator Laboratory is the host laboratory for US CMS, and U.S. scientists have designed, built and delivered to CERN several key elements of the CMS detector. Currently, U.S. contributions to CMS are more than 98 percent complete. A U.S. team from Fermilab recently carried out a precision mapping of the magnetic field of the CMS solenoid magnet that is being lowered today. By observing the curvature of the paths of charged particles in the magnetic field, physicists will calculate the energy of particles flying out from billions upon billions of proton-proton collisions that will occur inside the detector.

“We are proud of our contribution to the extraordinary international scientific endeavor now taking shape at the LHC,” said Associate Director for High Energy Physics at DOE's Office of Science Dr. Robin Staffin. “We applaud the engineering tour de force of today’s CMS milestone at CERN. Each step forward at the LHC experiments and the accelerator brings us closer to the start of scientific operations and to breakthroughs in our understanding of the physics of the universe.”

Experimenters have already lowered the first seven of 15 pieces of the CMS detector, with the first piece arriving in the experimental cavern on November 30, 2006. The giant section descending today marks the halfway point in the lowering process, with the last piece scheduled to make its descent in summer 2007. Particle detectors are typically assembled underground, where the accelerator tunnel is located. CMS has broken with tradition by starting assembly before completion of the underground cavern, taking advantage of a spacious surface assembly hall to preassemble and pretest the detector’s myriad components and systems.

“This is an impressive milestone in the complex installation of the CMS particle detector,” said Dr. Moishe Pripstein, Program Director at the National Science Foundation. “It augurs well for being ready for first beam collisions at the LHC. We are delighted that scientists from U.S. universities and from Fermilab are making substantial technical contributions to this grand international collaboration and look forward to exciting results in the next several years.”

Physicists are preparing the CMS detector and its sister detector, ATLAS, to take data at CERN’s Large Hadron Collider, where scientists predict that they will make fundamental discoveries about the universe, using very-high-energy proton collisions. Beyond revealing a new world of unknown particles, the LHC experiments could explain why those particles exist and behave as they do. They could discover the origins of mass, shed light on dark matter, uncover hidden symmetries of the universe, and possibly find extra dimensions of space.

UCR physicists are commissioning the experiment and preparing for analysis of data when the Large Hadron Collider turns on later in 2007. “We are concentrating on searches for the origin of electroweak symmetry breaking and for new physics,” Hanson said.

The United States contributions to the CMS experiment and the Large Hadron Collider are funded by the Department of Energy’s Office of Science and the National Science Foundation.

CERN is the European Organization for Nuclear Research, with headquarters in Geneva, Switzerland. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. India, Israel, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.

Fermi National Accelerator Laboratory is the host laboratory for the US CMS Collaboration. Fermilab is a Department of Energy National Laboratory operated under a contract with DOE by the Fermi Research Alliance.

The University of California, Riverside ( is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

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