Higgs particle
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| Composition | Elementary particle |
|---|---|
| Statistics | Bosonic |
| Status | A new particle with a mass of 125 GeV was discovered in 2012 and later confirmed to be the Higgs boson with more precise measurements. (See: Current status) |
| Symbol | H0 |
| Theorised | R. Brout, F. Englert, P. Higgs, G. S. Guralnik, C. R. Hagen, and T. W. B. Kibble (1964) |
| Discovered | Large Hadron Collider (2011–2013) |
| Mass | 125.09±0.21 (stat.)±0.11 (syst.) GeV/c2 (CMS+ATLAS) |
| Mean lifetime | 1.56×10−22 s (predicted) |
| Decays into | |
| Electric charge | 0 e |
| Colour charge | 0 |
| Spin | 0 |
| Weak isospin | −1/2 |
| Weak hypercharge | +1 |
| Parity | +1 |
The Higgs boson is an elementary particle in the Standard Model of particle physics. It is the quantum excitation of the Higgs field, a fundamental field of crucial importance to particle physics theory, first suspected to exist in the 1960s. Unlike other known fields such as the electromagnetic field, it has a non-zero constant value in vacuum. The question of the existence of the Higgs field became the last unverified part of the Standard Model of particle physics, and for several decades, was considered "the central problem in particle physics".
The presence of the field, now confirmed by experimental investigation, explains why some fundamental particles have mass when, based on the symmetries controlling their interactions, they should be massless. It also resolves several other long-standing puzzles, such as the reason for the extremely short range of the weak force.
Although the Higgs field is non-zero everywhere and its effects ubiquitous, proving its existence was far from easy. In principle, it can be proved to exist by detecting its excitations, which manifest as Higgs particles (the Higgs boson), but these are extremely difficult to produce and to detect. The importance of this fundamental question led to a 40 -year-search, and the construction of one of the world's most expensive and complex experimental facilities to date, CERN's Large Hadron Collider, in an attempt to create Higgs bosons and other particles for observation and study. On 4 July 2012, the discovery of a new particle with a mass between 125 and 127 GeV/c2 was announced; physicists suspected that it was the Higgs boson. Since then, the particle has been shown to behave, interact, and decay in many of the ways predicted for Higgs particles by the Standard Model, as well as having even parity and zero spin, two fundamental attributes of a Higgs boson. This also means it is the first elementary scalar particle discovered in nature. More studies are needed to verify with higher precision that the discovered particle has properties matching those predicted for the Higgs boson by the Standard Model, or whether, as predicted by some theories, multiple Higgs bosons exist.
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