Width and Partial Widths of Unstable Particles
High Energy Physics - Theory
2009-10-31 v2 High Energy Physics - Phenomenology
Abstract
In the gauge theory context, a definition of branching ratios and partial widths of unstable particles is proposed that satisfies the basic principles of additivity and gauge independence. A simpler definition, similar to the conventional one, is examined in the Z^0-boson case. In order to establish contact with experiment, we show that it leads to a peak cross section that justifies the expression used by the LEP Electroweak Working Group through next-to-next-to-leading order, provided that the pole rather than the on-shell mass and width of the Z^0 boson are employed.
Cite
@article{arxiv.hep-th/0005149,
title = {Width and Partial Widths of Unstable Particles},
author = {P. A. Grassi and B. A. Kniehl and A. Sirlin},
journal= {arXiv preprint arXiv:hep-th/0005149},
year = {2009}
}
Comments
8 pages, LaTex, no figures, macros included, A more complete theoretical discussion and applications to the Z^0 peak cross section are included