1998/02/28 by Fyodor V. Tkachov
Physics and Astronomy · #hep-ph
published as Proc. XXXIII PNPI Winter School on Nuclear and Particle Physics, ed. Ya.I.Azimov et al., S.Petersburg, PNPI, 1999, pp.166-181 · PS 8 pp. Final must-have version 16 Nov 98: many clarifications (NB: expanded remark 6 at end) thanks to relaxed formfactor. More at http://www.inr.ac.ru/~ftkachov/unstable/index.htm
arxiv created 1998/11/16 · arxiv updated 2009/11/30
The difficulties of perturbation theory associated with unstable fundamental fields (such as the lack of exact gauge invariance in each order) are cured if one constructs perturbative expansion directly for probabilities interpreted as distributions in kinematic variables. Such an expansion is made possible by the powerful method of non-Euclidean asymptotic operation [hep-ph/9703424].