Discrete symmetries on the light front and a general relation connecting the nucleon electric dipole and anomalous magnetic moments

We consider the electric dipole form factor, F_3(q^2), as well as the Diracand Pauli form factors, F_1(q^2) and F_2(q^2), of the nucleon in thelight-front formalism. We derive an exact formula for F_3(q^2) to complementthose known for F_1(q^2) and F_2(q^2). We derive the light-front representationof the discrete symmetry transformations and show that time-reversal- andparity-odd effects are captured by phases in the light-front wave functions. Wethus determine that the contributions to F_2(q^2) and F_3(q^2), Fock state byFock state, are related, independent of the fundamental mechanism through whichCP violation is generated. Our relation is not specific to the nucleon, but,rather, is true of spin-1/2 systems in general, be they lepton or baryon. Theempirical values of the anomalous magnetic moments, in concert with empiricalbounds on the associated electric dipole moments, can better constrain theoriesof CP violation. In particular, we find that the neutron and proton electricdipole moments echo the isospin structure of the anomalous magnetic moments,kappa^n ~ - kappa^p.Comment: 25 pages, 1 figure. Published version. Ref. adde