Goldstino
Encyclopedia
The goldstino is the Nambu-Goldstone fermion
emerging in the spontaneous breaking
of supersymmetry
. It is the close
analog of the Goldstone boson
controlling the spontaneous breakdown of
ordinary bosonic symmetry. As in the case of Goldstone bosons, it is massless, unless
there is also a little explicit supersymmetry breakdown on top of spontaneous breakdown, in which case it develops a small mass.
In theories where supersymmetry is a global symmetry
, the goldstino is an ordinary particle (possibly the lightest supersymmetric particle, responsible for dark matter
). In theories where supersymmetry is a local symmetry, the goldstino is absorbed by the gravitino
, the gauge field it couples to, becoming its longitudinal component, and giving it nonvanishing mass. This mechanism
is a close analog of the way the Higgs field gives nonzero mass to the W and Z bosons
. Vestigial bosonic superpartners of the goldstinos, called sgoldstino
s,
might also appear, but need not, as supermultiplets have been reduced to arrays.
Fermion
In particle physics, a fermion is any particle which obeys the Fermi–Dirac statistics . Fermions contrast with bosons which obey Bose–Einstein statistics....
emerging in the spontaneous breaking
Spontaneous symmetry breaking
Spontaneous symmetry breaking is the process by which a system described in a theoretically symmetrical way ends up in an apparently asymmetric state....
of supersymmetry
Supersymmetry
In particle physics, supersymmetry is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are known as superpartners...
. It is the close
analog of the Goldstone boson
Goldstone boson
In particle and condensed matter physics, Goldstone bosons or Nambu–Goldstone bosons are bosons that appear necessarily in models exhibiting spontaneous breakdown of continuous symmetries...
controlling the spontaneous breakdown of
ordinary bosonic symmetry. As in the case of Goldstone bosons, it is massless, unless
there is also a little explicit supersymmetry breakdown on top of spontaneous breakdown, in which case it develops a small mass.
In theories where supersymmetry is a global symmetry
Global symmetry
A global symmetry is a symmetry that holds at all points in the spacetime under consideration, as opposed to a local symmetry which varies from point to point.Global symmetries require conservation laws, but not forces, in physics.-See also:...
, the goldstino is an ordinary particle (possibly the lightest supersymmetric particle, responsible for dark matter
Dark matter
In astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...
). In theories where supersymmetry is a local symmetry, the goldstino is absorbed by the gravitino
Gravitino
The gravitino is the supersymmetric partner of the graviton, as predicted by theories combining general relativity and supersymmetry; i.e. supergravity theories...
, the gauge field it couples to, becoming its longitudinal component, and giving it nonvanishing mass. This mechanism
is a close analog of the way the Higgs field gives nonzero mass to the W and Z bosons
W and Z bosons
The W and Z bosons are the elementary particles that mediate the weak interaction; their symbols are , and . The W bosons have a positive and negative electric charge of 1 elementary charge respectively and are each other's antiparticle. The Z boson is electrically neutral and its own...
. Vestigial bosonic superpartners of the goldstinos, called sgoldstino
Sgoldstino
Sgoldstino is the proposed superpartner of goldstino. It is a boson....
s,
might also appear, but need not, as supermultiplets have been reduced to arrays.