Relativistic description of the image Original Research Article

A relativistic description of spin 3/2 resonances and their decay channels is presented by calculating their selfenergies and spectral functions. The full vector-spinor structure is taken into account. Special emphasis is put on the N∗(1520) and its decay channels πN, ρN and πΔ. All interactions are formulated such that the number of degrees of freedom of a spin 3/2 state remains the same for the free and the interacting theory. The obtained results are compared with several approximations frequently used to avoid the complicated vector-spinor structure. Since this structure is taken fully into account here, the quality of the approximations can be judged.