The Large Hadron Collider is a particle accelerator housed in a 27km circular tunnel underneath the border between France and Switzerland. The instrument allows scientists to smash protons together at extremely high speeds and it is hoped that this will tell them more about what happened in the first moments after the Big Bang. Experiments here may also demonstrate the existence of the Higgs boson, a particle which is postulated to confer mass to other particles.
When on 30 March 2010, the accelerator began colliding protons together with a total energy of 7,000 billion electon volts, it became the most powerful particle collider ever.
Image: Installation of the silicon tracking detector in the CMS experiment (credit: CERN)
The LHC investigates the first moments after the Big Bang.
Researchers introduce the Large Hadron Collider.
The Large Hadron Collider, constructed in tunnels below Geneva, is the world's largest particle accelerator. Scientists using the LHC will recreate conditions less than a billionth of a second after the Big Bang.
BBC News reports from the Large Hadron Collider.
Reporting from the Large Hadron Collider at CERN, David Shukman finds out what scientists hope the experiment will tell them.
The Large Hadron Collider (LHC) is the world's largest and most powerful particle collider, most complex experimental facility ever built, and the largest single machine in the world. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories. It lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the France–Switzerland border near Geneva, Switzerland. Its first research run took place from 30 March 2010 to 13 February 2013 at an initial energy of 3.5 teraelectronvolts (TeV) per beam (7 TeV total), almost 4 times more than the previous world record for a collider, rising to 4 TeV per beam (8 TeV total) from 2012. On 13 February 2013 the LHC's first run officially ended, and it was shut down for planned upgrades. 'Test' collisions restarted in the upgraded collider on 5 April 2015, reaching 6.5 TeV per beam on 20 May 2015 (13 TeV total, the current world record). Its second research run commenced on schedule, on 3 June 2015.
The aim of the LHC is to allow physicists to test the predictions of different theories of particle physics, including measuring the properties of the Higgs boson and searching for the large family of new particles predicted by supersymmetric theories, as well as other unsolved questions of physics.
The collider has four crossing points, around which are positioned seven detectors, each designed for certain kinds of research. The LHC primarily collides proton beams, but it can also use beams of lead nuclei. Proton–lead collisions were performed for short periods in 2013 and 2016, and lead–lead collisions took place in 2010, 2011, 2013, and 2015.
The LHC's computing grid is a world record holder. Data from collisions was produced at an unprecedented rate for the time of first collisions, tens of petabytes per year, a major challenge at the time, to be analysed by a grid-based computer network infrastructure connecting 140 computing centres in 35 countries – by 2012 the Worldwide LHC Computing Grid was also the world's largest distributed computing grid, comprising over 170 computing facilities in a worldwide network across 36 countries.