The scientists also accelerated a second beam of protons through the path in the opposite direction, the goal being head-on collisions of protons that can offer clues to the origin of mass and new forces and particles in the universe. The second beam made one turn around the LHC.

Celebrations across the United States and around the world mark the LHC's first circulating beams, an occasion more than 15 years in the making. An estimated 10,000 people from 60 countries have helped design and build the accelerator and its massive particle detectors, including more than 1,700 scientists, engineers, students and technicians from 94 U.S. universities and laboratories supported by the U.S. Department of Energy Office of Science and the National Science Foundation.

UCR faculty Robert Clare, John Ellison, J. William Gary, Gail Hanson and Stephen Wimpenny, along with postdoctoral scientists and graduate students are involved in the LHC's Compact Muon Solenoid (CMS) experiment, a large particle-capturing detector whose discoveries are expected to help answer questions such as: Are there undiscovered principles of nature? What is the origin of mass? Do extra dimensions exist? What is dark matter? How can we solve the mystery of dark energy? And how did the universe come to be?

"After many years of preparation, particle physics is taking a huge step towards understanding whether our theories about the origin of mass are correct and whether there is new physics that can explain dark matter and help us understand dark energy and the origin of the universe," said Hanson, a distinguished professor of physics, who currently is at CERN. "Particle physicists from UCR have been involved in the CMS experiment since its beginning, and have been working to construct and commission parts of the detector. They will soon be able to carry out the measurements and make the discoveries that have been dreamed of for so long."

It will take about a month for scientists to align the proton beams traveling in opposite directions in the LHC so that proton-proton collisions are generated. The LHC will create almost a billion such collisions per second at an energy of 14 trillion electron volts. These collisions will take place at four points around its 17-mile ring, where the four main LHC experiments, including CMS, are located.

"This is an extremely important moment," said Clare, a professor of physics. "We are now on the verge of making hopefully many discoveries over the next years in our understanding of particle physics and how the universe works. For the first time in a long time, we will be breaking new ground. We may discover the Higgs boson; we may discover supersymmetry. We may discover completely new and unexpected phenomena, which would be by far the most exciting prospect."

UCR postdoctoral researchers and students doing work related to the CMS experiment are: Avdhesh Chandra, Feng Liu, John Babb (currently at CERN), Geng-yuan "Greg" Jeng (currently at CERN), Shih-chuan "Kevin" Kao (currently at CERN), Hongliang Liu, Arun Luthra, Harold Nguyen, Robert Stringer (currently at CERN), Jared Sturdy (currently at CERN), Rachel Wilken, and Manatosh "Milton" Bose.

"As the largest and most powerful particle accelerator on Earth, the LHC represents a monumental technical achievement," said U.S. Department of Energy Undersecretary for Science Raymond L. Orbach, who is a former UCR Chancellor. "I congratulate the world's scientists and engineers who have made contributions to the construction of the accelerator for reaching this milestone. We now eagerly await the results that will emerge from operation of this extraordinary machine."

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