Gauge checks, consistency of approximation schemes and numerical evaluation of realistic scattering amplitudes
| dc.creator | Schwinn, Christian | |
| dc.date | 2003-07-04 | |
| dc.date | 2003-12-17 | |
| dc.date.accessioned | 2026-07-07T03:49:58Z | |
| dc.date.available | 2026-07-07T03:49:58Z | |
| dc.description | We discuss both theoretical tools to verify gauge invariance in numerical calculations of cross sections and the consistency of approximation schemes used in realistic calculations. A finite set of Ward Identities for 4 point scattering amplitudes is determined, that is sufficient to verify the correct implementation of Feynman rules of a spontaneously broken gauge theory in a model independent way. These identities have been implemented in the matrix element generator O'Mega and have been used to verify the implementation of the complete Standard Model in R_ξgauge. The consistency of approximation schemes in tree level calculations is discussed in the last part of this work. We determine the gauge invariance classes of spontaneously broken gauge theories, providing a new proof for the formalism of gauge and flavor flips. The schemes for finite width effects that have been implemented in O'Mega are reviewed. As a comparison with existing calculations, we study the consistency of these schemes in the process e^-e^+\to e^- \bar ν_e u\bar d. The violations of gauge invariance caused by the introduction of running coupling constants are analyzed. | |
| dc.description | LaTeX2e,170 pages (based on PhD thesis), ps and feynmp figures included, typos corrected | |
| dc.identifier | https://arxiv.org/abs/hep-ph/0307057 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/0307057 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/42619 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Gauge checks, consistency of approximation schemes and numerical evaluation of realistic scattering amplitudes | |
| dc.type | text |