Supersymmetry

Supersymmetry is a theoretical framework in physics that suggests the existence of a symmetry between particles with integer spin (bosons) and particles with half-integer spin (fermions). It proposes that for every known particle, there exists a partner particle with different spin properties.[1] There have been multiple experiments on supersymmetry that have failed to provide evidence that it exists in nature.[2] If evidence is found, supersymmetry could help explain certain phenomena, such as the nature of dark matter and the hierarchy problem in particle physics.

A supersymmetric theory is a theory in which 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 exist.[3] In theory, supersymmetry is a type of spacetime symmetry between two basic classes of particles: bosons, which have an integer-valued spin and follow Bose–Einstein statistics, and fermions, which have a half-integer-valued spin and follow Fermi–Dirac statistics.[4] The names of bosonic partners of fermions are prefixed with s-, because they are scalar particles. For example, if the electron exists in a supersymmetric theory, then there would be a particle called a selectron (superpartner electron), a bosonic partner of the electron.[5]

In supersymmetry, each particle from the class of fermions would have an associated particle in the class of bosons, and vice versa, known as a superpartner. The spin of a particle's superpartner is different by a half-integer. In the simplest supersymmetry theories, with perfectly "unbroken" supersymmetry, each pair of superpartners would share the same mass and internal quantum numbers besides spin. More complex supersymmetry theories have a spontaneously broken symmetry, allowing superpartners to differ in mass.[6][7][8]

Supersymmetry has various applications to different areas of physics, such as quantum mechanics, statistical mechanics, quantum field theory, condensed matter physics, nuclear physics, optics, stochastic dynamics, astrophysics, quantum gravity, and cosmology. Supersymmetry has also been applied to high energy physics, where a supersymmetric extension of the Standard Model is a possible candidate for physics beyond the Standard Model. However, no supersymmetric extensions of the Standard Model have been experimentally verified.[9][2]

  1. ^ "Supersymmetry". CERN. Archived from the original on 2023-07-14. Retrieved 2023-09-11.
  2. ^ a b Wolchover, Natalie (August 9, 2016). "What No New Particles Means for Physics". Quanta Magazine.
  3. ^ What is Supersymmetry?, Fermilab, 21 May 2013, retrieved 2023-09-30
  4. ^ Haber, Howie. "Supersymmetry, Part I (Theory)" (PDF). Reviews, Tables and Plots. Particle Data Group (PDG). Retrieved 8 July 2015.
  5. ^ Beringer, J. (2012). "SEARCHES FOR MONOPOLES, SUPERSYMMETRY, TECHNICOLOR, COMPOSITENESS, EXTRA DIMENSIONS, etc" (PDF). pdg.lbl.gov. Retrieved August 25, 2024.
  6. ^ Martin, Stephen P. (1997). "A Supersymmetry Primer". Perspectives on Supersymmetry. Advanced Series on Directions in High Energy Physics. Vol. 18. pp. 1–98. arXiv:hep-ph/9709356. doi:10.1142/9789812839657_0001. ISBN 978-981-02-3553-6. S2CID 118973381.
  7. ^ Baer, Howard; Tata, Xerxes (2006). Weak scale supersymmetry: From superfields to scattering events.
  8. ^ Dine, Michael (2007). Supersymmetry and String Theory: Beyond the Standard Model. Cambridge University Press. p. 169. ISBN 9780521858410.
  9. ^ Wolchover, Natalie (November 20, 2012). "Supersymmetry Fails Test, Forcing Physics to Seek New Ideas". Quanta Magazine.