3.2 The LHC and the Higgs
The Higgs is a new fundamental force of nature.
- The Higgs is the boson that was missing from our previous table of elementary particles, but it is not the same kind of boson as the others.
- The photon, gluon, W and Z bosons all have spin-1, whereas the Higgs is a spin-0 particle. In fact, the Higgs is the first elementary spin-0 particle ever discovered.
- The gauge bosons are responsible for carrying the fundamental forces, but for all practical purposes, we can call the Higgs a new fundamental force.
The Large Hadron Collider is the largest particle physics experiment ever assembled.
- The LHC is the world’s most powerful particle accelerator. Located at CERN (the European Organization for Nuclear Research) and built in collaboration with over 10,000 scientists from over a hundred different countries, the LHC aims to probe new and exotic areas of physics.
- The tunnel containing the collider is 27 km (17 mi) in circumference, and the LHC can achieve energies greater than any other machine on the planet.
- The first collisions at the LHC were on September 10, 2008, but nine days later, a faulty electrical connection led to damage of over 50 superconducting magnets, delaying operations by 14 months.
- When the research program resumed, scientists at the LHC were able to rediscover all previously discovered particles of the Standard Model (a century-long process) in just nine months.
One of the main missions of the LHC was to discover the Higgs boson.
- The LHC has seven different detectors, and two of them are large, general purpose particle detectors—ATLAS and CMS.
- The ATLAS experiment looks for new signs of physics beyond the Standard Model, including the origins of mass and extra dimensions. The Compact Muon Solenoid (CMS) experiment looks for clues as to what the universe is really made of and the properties of the Higgs boson.
- To handle the incredible volume of data produced by LHC collisions, the LHC Computing Grid was created. It is the world’s largest computing grid, comprising over 170 facilities in a network across 36 countries.
- By 2012, over 6 quadrillion proton-proton collisions had been analyzed, and the LHC was producing data at approximately 25 petabytes (25,000 terabytes) per year.
July 4th, 2012: A 'eureka' moment.
- The hunt for the Higgs boson was one that lasted decades.
- Experiment by experiment, the window for the mass of the Higgs was narrowed further and further.
- On July 4th, 2012, CERN announced that a massive 125 GeV boson had been detected. Further analysis confirmed that it was indeed the long-sought Higgs boson.
- The next steps are to study its properties—a mission that will require huge advances in both technology and theory.