Multipole expansion for the electron-nucleus scattering at high energies in the unified electroweak theory

The article presents the multipole expansion for the electron-nucleus scattering cross-section at high energies within framework of the unified electroweak theory. The electroweak currents of the nucleus is expanded into simple components with definite angular momentum, which are called the multipole form factors. The multipole expansion of the cross-section is a consequence of the above expansion. Besides the familiar electromagnetic form factors FxL , there are new form factors VLX and ALX related to weak interactions, corresponding to the vector and axial weak currents. The obtained general expressions are applied to the nucleus 36Li , where the partial form factors are computed in the multiparticle shell model.

Angular Momentum and Discrete Symmetries in the Spinor Bethe-Salpeter Equation

The group-theoretical basis for the angular momentum reduction of the spinor Bethe-Salpeter equation is discussed. We construct amplitude of definite angular momentum by analogy to the nonrelativistic problem and discuss the differences. The additional decomposition because of discrete symmetries is explained. Finally, we relate the states to those obtained in the non-relativistic quark model.