Point-Form Dynamics and Electromagnetic Properties of Few-Body Systems
Elmar P. Biernat
Sala P9, IST, Edifício Matemática
Tuesday, October 25th, 2011 at 04:00 PM
I will start with a brief introduction to the point-form of relativistic dynamics and discuss its applications to both quantum field theory and relativistic quantum mechanics (RQM). In the main part of my talk I will concentrate on the study of electromagnetic properties of few-body bound systems within point form RQM. To this end I will present a Poincare-invariant coupled-channel approach to investigate the electromagnetic structure of two-body bound states like the pion, the rho meson and the deuteron. In our formalism we use a Bakamjian-Thomas type mass operator which describes particle production and annihilation via vertex interactions that are derived from field theoretical interaction densities. I will sketch how an expression for the electromagnetic bound-state current can be extracted from the 1-photon-exchange optical potential of electron-bound-state scattering. The violation of cluster separability inherent in a Bakamjian-Thomas framework for more than 2 particles will be addressed and its consequences on the bound-state current will be discussed. I will also point out the similarities between our approach and covariant light-front approaches. Finally, I will present a Walecka-type model for the deuteron and give the numerical results for the form factors.
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