Relativistic description of the N*(1520)

摘要

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 pi N, rho N and pi Delta. 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. (c) 2006 Elsevier B.V. All rights reserved.