Solving the Bethe-Salpeter equation in Minkowski space
| Date/Time: | Wednesday, 06 May 2015 from 4:10 pm to 5:00 pm |
|---|---|
| Location: | A401 Zaffarano Hall |
| Contact: | |
| Phone: | 515-294-8894 |
| Channel: | College of Liberal Arts and Sciences |
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After a brief review of different approaches to the problem of few-body
relativistic systems, I explain a recently developed method of direct
solution of the Bethe-Salpeter equation in Minkowski space. We reproduce
the binding energies and phase shifts found by other methods. In addition,
the two-body off-mass shell scattering amplitude is computed for the first
time. Using this amplitude, we calculate the transition form factor for
electrodisintegration of a bound system. The gauge invariance, which manifests itself in conservation of the transition electromagnetic current, is studied numerically. The current is indeed conserved, but due to rather subtle cancellation, for any energy and momentum transfer, between two very different contributions: the plane wave (non-interacting final particles) and the final state interaction. This cancellation takes place provided the initial bound state Bethe-Salpeter amplitude, the final scattering state and the operator of electromagnetic current are strictly consistent with each other. A reliable result for the transition form factor can be obtained in the latter case only.