Large Hadron Collider

The Large Hadron Collider 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 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 27km in circumference, as deep as 175m beneath the France–Switzerland border near Geneva, Switzerland. Its first research run took place from March 2010 to early 2013 at an energy of 3.5 to 4 teraelectronvolts per beam, about 4 times the previous world record for a collider. Afterwards, the accelerator was upgraded for two years. It was restarted in early 2015 for its second research run, reaching 6.5 TeV per beam .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.