Gauge boson

Source: Wikipedia, the free encyclopedia.
The Standard Model of elementary particles, with the gauge bosons in the fourth column in red

In

fermions.[1][2] Elementary particles whose interactions are described by a gauge theory interact with each other by the exchange of gauge bosons, usually as virtual particles
.

W and Z bosons, and gluons are gauge bosons. All known gauge bosons have a spin of 1; for comparison, the Higgs boson has spin zero and the hypothetical graviton has a spin of 2. Therefore, all known gauge bosons are vector bosons
.

Gauge bosons are different from the other kinds of bosons: first, fundamental

composite bosons, made of quarks; third, larger composite, non-force-carrying bosons, such as certain atoms
.

Gauge bosons in the Standard Model

The

electromagnetic interaction; W and Z bosons, which carry the weak interaction; and gluons, which carry the strong interaction.[3]

Isolated gluons do not occur because they are colour-charged and subject to colour confinement.

Multiplicity of gauge bosons

In a

electroweak theory
.

Massive gauge bosons

Gauge invariance requires that gauge bosons are described mathematically by field
equations for massless particles. Otherwise, the mass terms add non-zero additional terms to the Lagrangian under gauge transformations, violating gauge symmetry. Therefore, at a naïve theoretical level, all gauge bosons are required to be massless, and the forces that they describe are required to be long-ranged. The conflict between this idea and experimental evidence that the weak and strong interactions have a very short range requires further theoretical insight.

According to the Standard Model, the W and Z bosons gain mass via the

LHC.[4]

Beyond the Standard Model

Grand unification theories

The Georgi–Glashow model predicts additional gauge bosons named X and Y bosons. The hypothetical X and Y bosons mediate interactions between quarks and leptons, hence violating conservation of baryon number and causing proton decay. Such bosons would be even more massive than W and Z bosons due to symmetry breaking. Analysis of data collected from such sources as the Super-Kamiokande neutrino detector has yielded no evidence of X and Y bosons.[citation needed]

Gravitons

The fourth fundamental interaction,

diffeomorphism invariance
.

W′ and Z′ bosons

Main article: W′ and Z′ bosons

W′ and Z′ bosons refer to hypothetical new gauge bosons (named in analogy with the Standard Model W and Z bosons).

See also

References

  1. ISBN 0-684-85578-X
    .
  2. ISBN 0-7607-4616-8.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  3. ISBN 981-238-149-X
    .
  4. ^ "CERN and the Higgs boson". CERN. Archived from the original on 23 November 2016. Retrieved 23 November 2016.

External links

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