The goldstino is the Nambu−Goldstone

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 ...

emerging in the spontaneous breaking of

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 ...

. It is the close fermionic analog of the Nambu−Goldstone bosons controlling the spontaneous breakdown of ordinary bosonic symmetries. As in the case of Goldstone bosons, it is massless, unless there is, in addition, a small explicit supersymmetry breakdown involved, on top of the basic spontaneous breakdown; in this case it develops a ''small'' mass, analogous to that of Pseudo-Goldstone bosons of chiral symmetry breaking. In theories where supersymmetry is a

global symmetry In physics, a symmetry of a physical system is a physical or mathematical feature of the system (observed or intrinsic) that is preserved or remains unchanged under some transformation. A family of particular transformations may be ''continuo ...

, the goldstino is an ordinary particle (possibly the lightest supersymmetric particle, responsible 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 ...

). In theories where supersymmetry is a

local symmetry In physics, a symmetry of a physical system is a physical or mathematical feature of the system (observed or intrinsic) that is preserved or remains unchanged under some transformation. A family of particular transformations may be ''continuo ...

, the goldstino is absorbed by 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 ...

, the

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) ...

it couples to, becoming its longitudinal component, and giving it nonvanishing mass. This mechanism is a close analog of the way 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 ...

gives nonzero mass to the

W and Z bosons 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 , , and ...

. Vestigial bosonic superpartners of the goldstinos, called ''

sgoldstino A sgoldstino is any of the spin-0 superpartners of the goldstino in relativistic quantum field theories with spontaneously broken supersymmetry. The term ''sgoldstino'' was first used in 1998. In 2016, Petersson and Torre hypothesized that a sg ...

s'', might also appear, but need not, as

supermultiplet In theoretical physics, a supermultiplet is a representation of a supersymmetry algebra. Then a superfield is a field on superspace which is valued in such a representation. Naïvely, or when considering flat superspace, a superfield can simply b ...

s have been reduced to arrays. In effect, SSB of supersymmetry, by definition, implies a

nonlinear realization In mathematical physics, nonlinear realization of a Lie group ''G'' possessing a Cartan subgroup ''H'' is a particular induced representation of ''G''. In fact, it is a representation of a Lie algebra \mathfrak g of ''G'' in a neighborhood of its ...

of the supersymmetry in the Nambu−Goldstone mode, in which the goldstino couples ''identically to all particles'' in these arrays, and is thus the superpartner of ''all of them'', equally.

References

Supersymmetric quantum field theory Hypothetical elementary particles {{Particle-stub