GIM mechanism

The GIM mechanism ( to Sheldon Lee Glashow, John Iliopolus, Luciano Maiani: 1970 ) is one in particle physics. Historically, he was the reason that led to the prediction of the charm quark.

It was known that the decay channel a very small branching ratio ( branching ratio), that is, has. This was far less than was expected at that time. To explain why the decay is strongly suppressed, led Glashow, Iliopoulos and Maiani 1970 hypothetically the charm quark one. This induced a further disintegration channel that was indistinguishable for the first, and thus destructively interfered with this. This destructive interference of the two decay channels is called the GIM mechanism. Allows an explanation for the small branching ratio was given.

The first experimental evidence of the charm quarks (see J / ψ meson ) finally succeeded in 1974 ( SLAC -SP -017 Collaboration ( JE Augustin et al. 1974) & E598 Collaboration ( JJ Aubert et al. 1974) ). With this prediction and the actual discovery of the charm quark GIM mechanism has contributed to the acceptance of the standard model of elementary particle physics.