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 superpartner (also sparticle) is a class of hypothetical

elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons. As a c ...

s predicted by

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 ...

, which, among other applications, is one of the well-studied ways to extend the

Standard Model The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...

high-energy physics Particle physics or high-energy physics is the study of fundamental particles and forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the stu ...

. When considering extensions of the

, the ''s-'' prefix from ''sparticle'' is used to form names of superpartners of the Standard Model

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 ...

s ( sfermions),Alexander I. Studenikin (ed.), ''Particle Physics in Laboratory, Space and Universe'', World Scientific, 2005, p. 327. e.g. the

stop squark In particle physics, a stop squark, symbol , is the superpartner of the top quark as predicted by supersymmetry (SUSY). It is a sfermion, which means it is a spin-0 boson (scalar boson). While the top quark is the heaviest known quark, the sto ...

. The superpartners of Standard Model

bosons In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value (0, 1, 2, ...). Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have half odd-integer ...

have an ''-ino'' (bosinos) appended to their name, e.g. gluino, the set of all gauge superpartners are called the gauginos.

Theoretical predictions

According to the

theory, each

should have a partner

boson In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value (0, 1, 2, ...). Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have half odd-intege ...

, the fermion's superpartner, and each boson should have a partner fermion. Exact ''unbroken'' supersymmetry would predict that a particle and its superpartners would have the same mass. No superpartners of the

particles have yet been found. This may indicate that supersymmetry is incorrect, or it may also be the result of the fact that supersymmetry is not an exact, ''unbroken'' symmetry of nature. If superpartners are found, their masses would indicate the scale at which supersymmetry is broken. For particles that are real scalars (such as an

axion An axion () is a hypothetical elementary particle originally theorized in 1978 independently by Frank Wilczek and Steven Weinberg as the Goldstone boson of Peccei–Quinn theory, which had been proposed in 1977 to solve the strong CP problem ...

), there is a fermion superpartner as well as a second, real scalar field. For axions, these particles are often referred to as axinos and saxions. In extended supersymmetry there may be more than one superparticle for a given particle. For instance, with two copies of supersymmetry in four dimensions, a photon would have two fermion superpartners and a scalar superpartner. In zero dimensions it is possible to have supersymmetry, but no superpartners. However, this is the only situation where supersymmetry does not imply the existence of superpartners.

Recreating superpartners

If the supersymmetry theory is correct, it should be possible to recreate these particles in high-energy

particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies to contain them in well-defined particle beam, beams. Small accelerators are used for fundamental ...

s. Doing so will not be an easy task; these particles may have masses up to a thousand times greater than their corresponding "real" particles. Some researchers have hoped the

Large Hadron Collider The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It was built by the CERN, European Organization for Nuclear Research (CERN) between 1998 and 2008, in collaboration with over 10,000 scientists, ...

CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Gene ...

might produce evidence for the existence of superpartner particles. However, as of 2018, no such evidence has been found.

References

{{Authority control Supersymmetric quantum field theory Particle physics

Theoretical predictions

Recreating superpartners

See also

References