Analysis of the byproducts of these collisions gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it.
These may become apparent only at high energies and for extremely short periods of time, and therefore may be hard or impossible to study in other ways.
To do such experiments there are two possible setups: The collider setup is harder to construct but has the great advantage that according to special relativity the energy of an inelastic collision between two particles approaching each other with a given velocity is not just 4 times as high as in the case of one particle resting (as it would be in non-relativistic physics); it can be orders of magnitude higher if the collision velocity is near the speed of light.
[2] The first serious proposal for a collider originated with a group at the Midwestern Universities Research Association (MURA).
This group proposed building two tangent radial-sector FFAG accelerator rings.
Gerard K. O'Neill proposed using a single accelerator to inject particles into a pair of tangent storage rings.
[6] The first electron-positron colliders were built in late 1950s-early 1960s in Italy, at the Istituto Nazionale di Fisica Nucleare in Frascati near Rome, by the Austrian-Italian physicist Bruno Touschek and in the US, by the Stanford-Princeton team that included William C.Barber, Bernard Gittelman, Gerry O’Neill, and Burton Richter.
Around the same time, the VEP-1 electron-electron collider was independently developed and built under supervision of Gersh Budker in the Institute of Nuclear Physics in Novosibirsk, USSR.
The first observations of particle reactions in the colliding beams were reported almost simultaneously by the three teams in mid-1964 - early 1965.
[7] In 1966, work began on the Intersecting Storage Rings at CERN, and in 1971, this collider was operational.
In 1968 construction began on the highest energy proton accelerator complex at Fermilab.
It was eventually upgraded to become the Tevatron collider and in October 1985 the first proton-antiproton collisions were recorded at a center of mass energy of 1.6 TeV, making it the highest energy collider in the world, at the time.
The energy had later reached 1.96 TeV and at the end of the operation in 2011 the collider luminosity exceeded 430 times its original design goal.
More than a dozen future particle collider projects of various types - circular and linear, colliding hadrons (proton-proton or ion-ion), leptons (electron-positron or muon-muon), or electrons and ions/protons - are currently under consideration for detail exploration of the Higgs/electroweak physics and discoveries at the post-LHC energy frontier.