# Vector boson

In particle physics, a vector boson is a boson whose spin equals one. The vector bosons that are regarded as elementary particles in the Standard Model are the gauge bosons, the force carriers of fundamental interactions: the photon of electromagnetism, the W and Z bosons of the weak interaction, and the gluons of the strong interaction.[1] Some composite particles are vector bosons, for instance any vector meson (quark and antiquark). During the 1970s and 1980s, intermediate vector bosons (the W and Z bosons, which mediate the weak interaction) drew much attention in particle physics.[2][3]

A pseudovector boson is a vector boson that has even parity, whereas "regular" vector bosons have odd parity. There are no fundamental pseudovector bosons, but there are pseudovector mesons

## In relation to the Higgs boson

Feynman diagram of the fusion of two electroweak vector bosons to the scalar Higgs boson, which is a prominent process of the generation of Higgs bosons at particle accelerators.
(The symbol q means a quark particle, W and Z are the vector bosons of the electroweak interaction. H0 is the Higgs boson.)

The W and Z particles interact with the Higgs boson as shown in the Feynman diagram.[4]

## Explanation

The name vector boson arises from quantum field theory. The component of such a particle's spin along any axis has the three eigenvaluesħ, 0, and +ħ (where ħ is the reduced Planck constant), meaning that any measurement of its spin can only yield one of these values. (This is true for massive vector bosons; the situation differs for massless particles such as the photon, for reasons beyond the scope of this article. See Wigner's classification.[5])

The space of spin states therefore is a discrete degree of freedom consisting of three states, the same as the number of components of a vector in three-dimensional space. Quantum superpositions of these states can be taken such that they transform under rotations just like the spatial components of a rotating vector[citation needed] (the so called 3 representation of SU(2)). If the vector boson is taken to be the quantum of a field, the field is a vector field, hence the name.

The boson part of the name arises from the spin-statistics relation, which requires that all integer spin particles be bosons.