POLARIZATION ASYMMETRIES IN FERMION-(ANTI)FERMION SCATTERINGS WITH DIRAC, PAULI, SCALAR, TENSOR AND AXIAL COUPLING FACTORS

Abstract

The general helicity amplitudes and all the polarization asymmetries have been evaluated for the scattering of (i) two different fermions, (ii) two identical fermions, and (iii) a fermionantifermion pair. The interaction includes the electric and magnetic vertices (with coupling parameters e and a, respectively) for vector bosons as well as scalar and tensor couplings. And all these interactions contain their axial parts. Symmetries and substitution rules for helicity amplitudes are studied in detail. The amplitudes are explicitly given in the lowest order of perturbation expansion, but all with form factors instead of point vertices. The polarization asymmetries are generally defined and evaluated for colliding beams. The contribution of the magnetic interaction increases with energy, becomes dominant for E>mf/a or approximately E>2m2, and shows large polarization asymmetries.