Nonperturbative calculation of Green and vertex functions in terms of particle contours
Abstract
Description
The infrared regime of fermionic Green and vertex functions is studied analytically within a geometric approach which simulates soft interactions by an {\it effective} theory of contours. Expanding the particle path integral in terms of dominant contours at large distances, all-order results in the coupling constant are obtained for the renormalized fermion propagator and a universal vertex function with physical characteristics close to those associated with the Isgur-Wise function in the weak decays of heavy mesons. The extension to the ultraviolet regime is scetched.
LaTeX, using Worldstyle and comprising three eps files (7 pages in total). Invited talk presented at the International Conference Problems of Quantum Field Theory, May 13 - 18, 1996, Alushta, Crimea, Ukraine. To appear in the Proceedings
LaTeX, using Worldstyle and comprising three eps files (7 pages in total). Invited talk presented at the International Conference Problems of Quantum Field Theory, May 13 - 18, 1996, Alushta, Crimea, Ukraine. To appear in the Proceedings