Effective weak Lagrangians in the Standard Model and B decays

Weak processes (e.g., B decays) with characteristic energies <<M_W can be described by an effective theory which does not contain W, Z and other heavy particles (Higgs, t). Its Lagrangian contains four-fermion interaction operators. Essentially it is the theory proposed by Fermi and improved by Feynman, Gell-Mann, Marshak, Sudarshan.