In supersymmetry theories of
particle physics
Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the s ...
, a gaugino is the hypothetical
fermion
In particle physics, a fermion is a subatomic particle that follows Fermi–Dirac statistics. Fermions have a half-integer spin (spin 1/2, spin , Spin (physics)#Higher spins, spin , etc.) and obey the Pauli exclusion principle. These particles i ...
ic supersymmetric
field quantum (
superpartner
In particle physics, a superpartner (also sparticle) is a class of hypothetical elementary particles predicted by supersymmetry, which, among other applications, is one of the well-studied ways to extend the Standard Model of high-energy physics.
...
) of a
gauge field
In physics, a gauge theory is a type of field theory in which the Lagrangian, and hence the dynamics of the system itself, does not change under local transformations according to certain smooth families of operations (Lie groups). Formally, t ...
, as predicted by
gauge theory
In physics, a gauge theory is a type of field theory in which the Lagrangian, and hence the dynamics of the system itself, does not change under local transformations according to certain smooth families of operations (Lie groups). Formally, t ...
combined with
supersymmetry
Supersymmetry is a Theory, theoretical framework in physics that suggests the existence of a symmetry between Particle physics, particles with integer Spin (physics), spin (''bosons'') and particles with half-integer spin (''fermions''). It propo ...
. All gauginos have a spin of 1/2, except for the gravitino, which has a spin of 3/2.
In the
minimal supersymmetric extension of the standard model the following gauginos exist:
* The
gluino (symbol ) is the superpartner of the
gluon
A gluon ( ) is a type of Massless particle, massless elementary particle that mediates the strong interaction between quarks, acting as the exchange particle for the interaction. Gluons are massless vector bosons, thereby having a Spin (physi ...
, and hence carries
color charge
Color charge is a property of quarks and gluons that is related to the particles' strong interactions in the theory of quantum chromodynamics (QCD). Like electric charge, it determines how quarks and gluons interact through the strong force; ho ...
.
* The
gravitino (symbol ) is the supersymmetric partner of the
graviton
In theories of quantum gravity, the graviton is the hypothetical elementary particle that mediates the force of gravitational interaction. There is no complete quantum field theory of gravitons due to an outstanding mathematical problem with re ...
.
* Three winos (symbol and W͂
3) are the superpartners of the
W boson
In particle physics, the W and Z bosons are vector bosons that are together known as the weak bosons or more generally as the intermediate vector bosons. These elementary particles mediate the weak interaction; the respective symbols are , , an ...
s of the SU(2)
L gauge fields.
* The bino is the superpartner of the U(1) gauge field corresponding to
weak hypercharge
In the Standard Model (mathematical formulation), Standard Model of electroweak interactions of particle physics, the weak hypercharge is a quantum number relating the electric charge and the third component of weak isospin. It is frequently deno ...
.
Sometimes the term "electroweakinos" is used to refer to winos and binos and on occasion also higgsinos.
Note that in other SUSY models the zino () is the superpartner of the Z boson.
Mixing
Gauginos mix with
higgsinos, the superpartners of the
Higgs field
The Higgs boson, sometimes called the Higgs particle, is an elementary particle in the Standard Model of particle physics produced by the excited state, quantum excitation of the Higgs field,
one of the field (physics), fields in particl ...
's degrees of freedom, to form
mass eigenstates called
neutralinos, which are electrically neutral, and
charginos, which are electrically charged.
In many supersymmetric models, the
lightest supersymmetric particle (LSP), often a
neutralino such as the
photino, is stable. In that case it is a
weakly interacting massive particle
Weakly interacting massive particles (WIMPs) are hypothetical particles that are one of the proposed candidates for dark matter.
There exists no formal definition of a WIMP, but broadly, it is an elementary particle which interacts via gravity an ...
(WIMP) and a candidate for
dark matter
In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...
.
See also
*
Gaugino condensation
In quantum field theory, gaugino condensation is the nonzero vacuum expectation value in some models of a bilinear expression constructed in theories with supersymmetry from the superpartner of a gauge boson called the gaugino. The gaugino and t ...
References
*
Supersymmetric quantum field theory
Hypothetical elementary particles
{{Particle-stub