Key Concepts

• The Large Hadron Collider (LHC), the biggest and most complicated particle physics experiment ever seen, is nearing completion and is scheduled to start operating this year.
• The LHC will accelerate bunches of protons to the highest energies ever generated by a machine, colliding them head-on 30 million times a second, with each collision spewing out thousands of particles at nearly the speed of light.
• Physicists expect the LHC to bring about a new era of particle physics in which major conundrums about the composition of matter and energy in the universe will be resolved.

You could think of it as the biggest, most powerful microscope in the history of science. The Large Hadron Collider (LHC), now being completed underneath a circle of countryside and villages a short drive from Geneva, will peer into the physics of the shortest distances (down to a nano-nanometer) and the highest energies ever probed. For a decade or more, particle physicists have been eagerly awaiting a chance to explore that domain, sometimes called the tera­scale because of the energy range involved: a trillion electron volts, or 1 TeV. Significant new physics is expected to occur at these energies, such as the elusive Higgs particle (believed to be responsible for imbuing other particles with mass) and the particle that constitutes the dark matter that makes up most of the material in the universe.

The mammoth machine, after a nine-year construction period, is scheduled (touch wood) to begin producing its beams of particles later this year. The commissioning process is planned to proceed from one beam to two beams to colliding beams; from lower energies to the tera­scale; from weaker test intensities to stronger ones suitable for producing data at useful rates but more difficult to control. Each step along the way will produce challenges to be overcome by the more than 5,000 scientists, engineers and students collaborating on the gargantuan effort. When I visited the project last fall to get a firsthand look at the preparations to probe the high-energy frontier, I found that everyone I spoke to expressed quiet confidence about their ultimate success, despite the repeatedly delayed schedule. The particle physics community is eagerly awaiting the first results from the LHC. Frank Wil­czek of the Massachusetts Institute of Technology echoes a common sentiment when he speaks of the prospects for the LHC to produce “a golden age of physics.”

   
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