At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. They use the world's largest and most complex scientific instruments to study the basic constituents of matter – the fundamental particles. The particles are made to collide together at close to the speed of light. The process gives the physicists clues about how the particles interact, and provides insights into the fundamental laws of nature.
The instruments used at CERN are purpose-built particle accelerators and detectors. Accelerators boost beams of particles to high energies before the beams are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.


CERN: Return of the LHC

On Friday, the Large Hadron Collider (LHC) opened its doors to allow particles to travel around the ring for the first time since the year-end technical stop (YETS) began in December 2015. At 10.30 am, a first bunch was circulating and by midday the beam was circulating in both directions.
30 Mar 2016