Proton Smasher Back On-Line

Protons at the European Laboratory for Particle Physics’ Large Hadron Collider (LHC) made their first collisions on Nov. 23, after the world’s most expensive and potentially most powerful particle accelerator went off-line in September 2008 just days after its launch. Costing nearly $10 billion, the accelerator is an international endeavor that includes scientists from across Europe, the U.S., India, and Japan. The U.S. has contributed $531 million to the project in cash and in-kind contributions, says James Strait, a member of the U.S. team at Fermi National Accelerator Laboratory. Located just outside Geneva, LHC’s 17-mile-long circular track is designed to collide protons at 7 trillion eV, in the hopes of finding the elusive Higgs boson and learning about the early moments of our universe. The first measured collisions were from protons injected at relatively lower energy—450 billion eV—as engineers adjusted beam lines. Real experiments at higher energies are planned in the next weeks.