The discovery of the fundamental particles of the Universe allowed physicists to gain a new insight on what the conditions during the Big Bang was like. Using particle accelerators, physicists are able to imitate the extreme conditions that occurred a fraction of the nanosecond after the Big Bang. Particle accelerators such as SLAC and the Large Hadron Collider (LHC) in particular are specialised at testing the different theories of particle physics.
The LHC is run by a multinational European organisation CERN, whose main aim is to provide the infrastructure needed to conduct experiments involving particle physics. The LHC is also the largest and most powerful particle collider in the world. The collider is designed in a circular fashion, with a circumference of approximately 27 kilometres, and it is buried between 50-125 metres underground, on the outskirts of Geneva, Switzerland. Inside the collider, there are two particle beams carrying hydrogen ions (protons) which run in opposite directions very close to the speed of light, before they are made to collide into one another. These particle beams travel through this circular tube with the guide of superconducting electromagnets, which provides a strong magnetic field, along with conducting electricity by chilling those magnets to -271.3°C using liquid helium. These magnets control the projection of the particle beams and also increase the chances of collision. The beams are made to collide at four particle detectors throughout the ring; ATLAS, CMS, ALICE and LHCb. When protons collide, many particles are scattered in all directions, which may further decay into other particles. Using this method, in 2012, scientists have observed a new, unstable particle, called the Higgs boson, named after Peter Higgs, who hypothesised its existence in 1964.
The Higgs field is accompanied by Higgs bosons, and any particle that interact with Higgs bosons are given mass and therefore cannot travel at the speed of light. Quarks and leptons interact with this field, so it bears a certain mass, whereas photons and gluons don’t interact with this field at all, so there is no mass in these particles, and they are able to travel at the speed of light.
Written By Kevin Huynh, Year 11.