Large Hadron Collider

The Large Hadron Collider (LHC) is world's largest and highest-energy particle accelerator. It was built by the European Organization for Nuclear Research (CERN) from 1998 to 2008, with the aim of allowing physicists to test the predictions of different theories of particle physics and high-energy physics, and particularly that of the existence of the hypothesized Higgs boson[1] and of the large family of new particles predicted by supersymmetric theories.[2] The LHC is expected to address some of the most fundamental questions of physics, advancing human understanding of the deepest laws of nature. It contains six detectors each designed for specific kinds of exploration.

The LHC lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the Franco-Swiss border near Geneva, Switzerland. Its synchrotron is designed to collide opposing particle beams of either protons at up to 7 teraelectronvolts (7 TeV or 1.12 microjoules) per nucleon, or lead nuclei at an energy of 574 TeV (92.0 µJ) per nucleus (2.76 TeV per nucleon-pair).[3][4] It was built in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories.[5]

On 10 September 2008, the proton beams were successfully circulated in the main ring of the LHC for the first time,[6] but 9 days later operations were halted due to a magnet quench incident resulting from an electrical fault. The ensuing helium gas explosion damaged over 50 superconducting magnets and their mountings, and contaminated the vacuum pipe.[7][8] On 20 November 2009 proton beams were successfully circulated again,[9][10] with the first recorded proton–proton collisions occurring 3 days later at the injection energy of 450 GeV per beam.[11] On 30 March 2010, the first collisions took place between two 3.5 TeV beams, setting the current world record for the highest-energy man-made particle collisions,[12] and the LHC began its planned...