supersymmetry

definition: A symmetry that can be applied to elementary particles so as to include both bosons and fermions. In the simplest supersymmetry theories, every boson has a corresponding fermion partner and every fermion has a corresponding boson partner. The boson partners of existing fermions have names formed by adding 's' to the beginning of the name of the fermion, e.g. selectron, squark, and slepton. The fermion partners of existing bosons have names formed by replacing '-on' at the end of the boson's name by '-ino' or by adding '-ino', e.g. gluino, photino, wino and zino. The infinities that cause problems in relativistic quantum field theories are less severe in supersymmetry theories because infinities of bosons and fermions cancel one another out. If supersymmetry is relevant to observed elementary particles, then it must be a broken symmetry, although there is no convincing evidence at present to show at what energy it would be broken. There ism in fact, no experimental evidence for the theory, although it is thought that it may form part of a unified theory of interactions. This would not necessarily by a unified-field theory; the idea of strings with supersymmetry may be the best approach to unifying the four fundamental interactions.