In supersymmetry theories of
particle physics
Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...
, a gaugino is the hypothetical
fermion
In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Generally, it has a half-odd-integer spin: spin , spin , etc. In addition, these particles obey the Pauli exclusion principle. Fermions include all quarks an ...
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 (is invariant) under local transformations according to certain smooth families of operations (Lie groups) ...
, 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 (is invariant) under local transformations according to certain smooth families of operations (Lie groups) ...
combined with
supersymmetry
In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theories e ...
. All gauginos have spin 1/2, except for gravitino (spin 3/2).
In the
minimal supersymmetric extension of the standard model the following gauginos exist:
* The
gluino In supersymmetry, a gluino (symbol ) is the hypothetical supersymmetric partner of a gluon.
In supersymmetric theories, gluinos are Majorana fermions and interact via the strong force as a color octet. Gluinos have a lepton number 0, baryon number ...
(symbol ) is the superpartner of the
gluon
A gluon ( ) is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quarks. It is analogous to the exchange of photons in the electromagnetic force between two charged particles. Gluons bind q ...
, 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).
The "color charge" of quarks and gluons is completely unrelated to the everyday meanings of ...
.
* The
gravitino
In supergravity theories combining general relativity and supersymmetry, the gravitino () is the gauge fermion supersymmetric partner of the hypothesized graviton. It has been suggested as a candidate for dark matter.
If it exists, it is a f ...
(symbol ) is the supersymmetric partner of the
graviton
In theories of quantum gravity, the graviton is the hypothetical quantum of gravity, an elementary particle that mediates the force of gravitational interaction. There is no complete quantum field theory of gravitons due to an outstanding mathem ...
.
* Three winos (symbol and W͂
3) are the superpartners of the
W bosons 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 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 denoted Y_\mathsf and corresponds to the gauge ...
.
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
higgsino
In particle physics, for models with N=1 supersymmetry a higgsino, symbol , is the superpartner of the Higgs field. A higgsino is a Dirac fermionic field with spin and it refers to a weak isodoublet with hypercharge half under the Standard Mo ...
s, 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 quantum excitation of the Higgs field,
one of the fields in particle physics theory. In the Stand ...
's degrees of freedom, to form
mass eigenstate
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementa ...
s called
neutralino
In supersymmetry, the neutralino is a hypothetical particle. In the Minimal Supersymmetric Standard Model (MSSM), a popular model of realization of supersymmetry at a low energy, there are four neutralinos that are fermions and are electrically ...
s, which are electrically neutral, and
chargino
In particle physics, the chargino is a hypothetical particle which refers to the mass eigenstates of a charged superpartner, i.e. any new electrically charged fermion (with spin 1/2) predicted by supersymmetry. They are linear combinations of t ...
s, which are electrically charged.
In many supersymmetric models, the
lightest supersymmetric particle (LSP), often a
neutralino
In supersymmetry, the neutralino is a hypothetical particle. In the Minimal Supersymmetric Standard Model (MSSM), a popular model of realization of supersymmetry at a low energy, there are four neutralinos that are fermions and are electrically ...
such as the
photino
A photino is a hypothetical subatomic particle, the fermion WIMP superpartner of the photon predicted by supersymmetry. It is an example of a gaugino. Even though no photino has ever been observed so far, it is one of the candidates for the light ...
, is stable. In that case it is a
WIMP
Wimp, WIMP, or Wimps may refer to:
Science and technology
* Weakly interacting massive particle, a hypothetical particle of dark matter
* WIMP (computing), the "window, icon, menu, pointer" paradigm
* WIMP (software bundle), the web stack of Wind ...
and a candidate for
dark matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab ...
.
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