Breit-Wigner formalism for non-Abelian theories
Abstract
Description
The consistent description of resonant transition amplitudes within the framework of perturbative field theories necessitates the definition and resummation of off-shell Green's functions, which must respect several crucial physical requirements. In particular, the generalization of the usual Breit-Wigner formalism in a non-Abelian context constitutes a highly non-trivial problem, related to the fact that the conventionally defined Green's functions are unphysical. We briefly review the main field-theoretical difficulties arising when attempting to use such Green's functions outside the confines of a fixed order perturbative calculation, and explain how this task has been successfully accomplished in the framework of the pinch technique.
10 pages, plain Latex, 4 Figures in a separate ps. file; based on talk presented at ``50 Years of Electroweak Physics: A symposium in honor of Professor Alberto Sirlin's 70th Birthday'', New York University, New York, October 27-28, 2000
10 pages, plain Latex, 4 Figures in a separate ps. file; based on talk presented at ``50 Years of Electroweak Physics: A symposium in honor of Professor Alberto Sirlin's 70th Birthday'', New York University, New York, October 27-28, 2000