GIM mechanism

In quantum field theory, the GIM mechanism (or Glashow–Iliopoulos–Maiani mechanism) is the mechanism by which flavour-changing neutral currents (FCNCs) are suppressed. It also explains why weak interactions that change strangeness by 2 (ΔS = 2 transitions) are suppressed while those that change strangeness by 1 (ΔS = 1 transitions) are allowed. The mechanism was put forth by Sheldon Lee Glashow, John Iliopoulos and Luciano Maiani in their famous paper "Weak Interactions with Lepton–Hadron Symmetry" published in Physical Review D in 1970.[1]

At the time the GIM mechanism was proposed, only three quarks (up, down, and strange) were thought to exist. Glashow and James Bjorken predicted a fourth quark in 1964,[2] but there was little evidence for its existence. The GIM mechanism however, required the existence of a fourth quark, and the prediction of the charm quark is usually credited to Glashow, Iliopoulos, and Maiani.

References

  1. S.L. Glashow, J. Iliopoulos, L. Maiani (1970). "Weak Interactions with Lepton–Hadron Symmetry". Physical Review D 2 (7): 1285. Bibcode:1970PhRvD...2.1285G. doi:10.1103/PhysRevD.2.1285.
  2. B.J. Bjorken, S.L. Glashow (1964). "Elementary particles and SU(4)". Physics Letters 11 (3): 255–257. Bibcode:1964PhL....11..255B. doi:10.1016/0031-9163(64)90433-0.

Further reading