ON THE THEORY OF INTERACTING FIELDS IN FOLDY-WOUTHUYSEN REPRESENTATION

V. P. Neznamov

This review is devoted to formulation of quantum electrodynamics (QED) and Standard Model in Foldy-Wouthuysen representation. Hamiltonian HFW in the form of a series of charge e powers is obtained as applied to electromagnetic interaction in FW representation. This paper considers quantum electrodynamics in the lowest-order theory of perturbations. Computations of the certain QED processes have been carried out. For external fermion lines (pf2 = mf2), the possibility of the scattering matrix expansion in powers of the coupling constant with matrix elements containing no terms with fermion propagators is demonstrated. To include the interaction of real particles with antiparticles, the modification to Foldy-Wouthuysen representation has been proposed. Fermions in the modified FW representation can be present in one of the two possible states characterized by the sign of the third component of isotopic spin (Tf3). The sign of Tf3 is related to the sign of mass terms in the modified Hamiltonian HFW. Real fermions (pf2 = mf2) can interact with each other, real antifermions can also interact with each other, however, real fermions of a certain sign of Tf3 can interact only with real antifermions of an opposite sign of Tf3, and vice versa. The formulation of the Standard Model in the FW representation doesn't require necessary interactions of Higgs bosons with fermions to provide SU(2) invariance. With such an approach, the sector of Higgs bosons converges significantly: Higgs bosons are responsible for gauge invariance of the theory alone and interact only with gauge bosons. QED in the FW representation is invariant relative to C, P, T inversions. Weak interaction doesn't preserve C and P parity, however, it preserves the combined CP parity. The theory has a possibility of attributing the CP symmetry violation to full or partial violation of the isotopic symmetry in the modified Foldy-Wouthuysen representation.

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