CERN collider achieves record collision rate
DOI: 10.1063/1.3603910
CERN collider achieves record collision rate. The Large Hadron Collider at CERN has reached a milestone in its quest to find—or lay to rest—the Higgs boson predicted by particle theory’s standard model. The LHC produces 7-TeV head-on collisions between protons in countercirculating beams stored in its 27-km-circumference ring, part of which is shown here. On 22 April, the colliding beams achieved a record luminosity of 4.7 × 1032/(cm2 s), surpassing for the first time the previous record held by the 2-TeV Tevatron col-lider at Fermilab. The new record luminosity (defined as the collision rate per unit scattering cross section) translates into 50 million proton–proton collisions per second at each of the LHC detectors. If the standard-model Higgs exists, it will be produced in only a tiny fraction of those collisions. But given the new record luminosity, the LHC detectors should accumulate enough data by the end of 2012 to provide a statistically robust sighting of the Higgs somewhere in the mass range (115–155 GeV) from which it has not already been excluded—or to demonstrate that Nature here parts company with the standard model. To allow that decisive accumulation of data, the start of the 18-month shutdown required to bring the LHC up to its full 14-TeV design energy has now been postponed from the end of this year to the end of 2012. (
