Nepedia
Back to Discover
Advanced Reader
⚛️

Supersymmetry

physical science Maturity 13-18 Next article →

Supersymmetry, often called SUSY, is a theoretical framework in physics. It suggests a deep symmetry between two fundamental classes of particles. These classes are bosons and fermions. Bosons are particles with integer spin that follow Bose–Einstein statistics. Fermions are particles with half-integer spin that follow Fermi–Dirac statistics. In a supersymmetric theory, the equations for force and the equations for matter become identical. This creates a spacetime symmetry between these two different types of particles. Scientists study SUSY to find a way to go beyond the Standard Model of physics.

The core mechanism of supersymmetry involves the concept of superpartners. Every known particle is proposed to have a partner particle with different spin properties. If a fermion exists, it must have an associated boson partner. If a boson exists, it must have an associated fermion partner. In the simplest theories, known as unbroken supersymmetry, these pairs share the same mass. They also share the same internal quantum numbers, except for their spin. However, more complex theories involve spontaneously broken symmetry. This allows the superpartners to have different masses than their original counterparts.

Naming these particles follows a specific rule in theoretical physics. The bosonic partners of fermions are given a prefix of "s-" because they are scalar particles. For example, if an electron is a fermion, its bosonic superpartner would be called a selectron. This naming convention helps physicists keep track of the different types of particles in their mathematical models. By linking these two classes, supersymmetry provides a way to unify the different aspects of the microscopic world. This connection is a major goal for researchers working in high-energy physics.

The history of supersymmetry spans several decades of discovery. Hironari Miyazawa first proposed a version of this symmetry in 1966. His work focused on hadronic physics and the relationship between mesons and baryons. This early version was an internal symmetry and was considered badly broken. In 1971, several scientists independently rediscovered supersymmetry in the context of quantum field theory. J. L. Gervais and B. Sakita, as well as Yu. A. Golfand and E. P. Likhtman, all made important contributions that year. D. V. Volkov and V. P. Akulov also discovered it in 1972. The term "supersymmetry" was later coined in 1974 by Abdus Salam and John Strathdee.

Mathematical structures are vital to understanding how these symmetries function. Supersymmetries are generated by objects that transform by spin representations. To combine bosons and fermions into a single algebra, scientists use a Z2-grading. In this system, bosons are treated as even elements and fermions as odd elements. This mathematical structure is known as a Lie superalgebra. One of the most important versions is the Super-Poincaré algebra. This algebra allows for the extension of the Poincaré group, which describes the symmetries of spacetime. This mathematical loophole is unique because it allows spacetime and internal symmetries to combine.

Supersymmetry has many important applications across different scientific fields. In particle physics, Pierre Fayet proposed the Minimal Supersymmetric Standard Model, or MSSM, in 1977. This model was designed to help solve the hierarchy problem. The theory also has uses in quantum mechanics, statistical mechanics, and nuclear physics. In the field of optics, researchers use SUSY to explore how light moves through structures. In condensed matter physics, SUSY concepts help model complex systems. For example, in 2022, researchers used computer simulations to study atoms with supersymmetric topological quasiparticles.

Despite its mathematical beauty, supersymmetry remains unproven in the physical world. Many experiments have been conducted to find evidence of superpartner particles. So far, no experiment has successfully verified a supersymmetric extension of the Standard Model. Because of this lack of evidence, some physicists argue that the theory may be dead. However, the theory remains a vital part of many proposed models in cosmology and quantum gravity. It continues to offer a way to explore the nature of dark matter and the fundamental structure of the universe.

653 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (1)
File:Hqmc-vector.svg
Hqmc-vector.svg
More to explore

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.