The Complex-Mass Scheme and Unitarity in perturbative Quantum Field Theory
High Energy Physics - Phenomenology
2015-09-08 v2 High Energy Physics - Theory
Abstract
We investigate unitarity within the Complex-Mass Scheme, a convenient universal scheme for perturbative calculations involving unstable particles in Quantum Field Theory which guarantees exact gauge invariance. Since this scheme requires to introduce complex masses and complex couplings, the Cutkosky cutting rules, which express perturbative unitarity in theories of stable particles, are no longer valid. We derive corresponding rules for scalar theories with unstable particles based on Veltman's Largest-Time Equation and prove unitarity in this framework.
Keywords
Cite
@article{arxiv.1406.6280,
title = {The Complex-Mass Scheme and Unitarity in perturbative Quantum Field Theory},
author = {Ansgar Denner and Jean-Nicolas Lang},
journal= {arXiv preprint arXiv:1406.6280},
year = {2015}
}
Comments
25 pages, PDFLaTeX, PDF figures, improved and slightly extended version appeared in European Physics Journal C