Study of Trilinear Gauge Boson Couplings at the Tevatron Collider

TL;DR

This paper surveys Tevatron Run I measurements of trilinear gauge boson couplings using CDF and DØ data, interpreted with an effective Lagrangian framework. It covers WWγ, WWZ, Zγ, and related diboson channels, including form-factor unitarization and indirect precision constraints. The combined analyses yield the strongest direct limits to date on anomalous couplings and provide the first direct evidence for a nonzero WWZ coupling. It discusses future sensitivity at LEP II, the LHC, and NLC, outlining how higher energy and luminosity will probe new-physics scales beyond the SM.

Abstract

We review studies of the trilinear gauge boson couplings at the Tevatron proton-antiproton collider from data collected by the CDF and D0 collaborations during the period 1992--1996. The gauge boson couplings are a fundamental prediction of the standard model, resulting from the non-Abelian nature of the theory. Therefore, experimental tests of the couplings are of foremost importance. We introduce the experimental results by reviewing the effective Lagrangian formalism, the indirect constraints on the couplings from low-energy experiments, and the expected values of the couplings in theories beyond the standard model. Finally, we consider the prospects for future measurements.

Figures (18)

• Figure 1: Leading-order Feynman diagrams for vector boson pair production. The assignments of $V_0$, $V_1$, and $V_2$ are: $V_0=V_1=W$ and $V_2=\gamma$ for $W\gamma$ production; $V_0=\gamma$ or $Z$, $V_1=W^+$ and $V_2=W^-$ for $WW$ production; $V_0=V_1=W$ and $V_2=Z$ for $WZ$ production; and $V_0=\gamma$ or $Z$, $V_1=Z$ and $V_2=\gamma$ for $Z\gamma$ production.
• Figure 2: Leading-order Feynman diagram for $W$ production with radiative $W$ decay: The charged lepton radiates a photon by bremsstrahlung.
• Figure 3: Photon transverse momentum spectra for (a) $W\gamma$ production and (b) $Z\gamma$ production at the Tevatron for SM and anomalous couplings. From Refs. BaurBerger-wgmc and zg-nlo.
• Figure 4: Experimental 95% confidence level limits and unitarity limits as a function of form factor scale $\Lambda_{FF}$ for (a) the $ZZ\gamma$ coupling $h^Z_{30}$ and (b) the $WW\gamma$ coupling $\Delta\kappa$ [from cdf_wgzg1a_prd]. Note that the experimental limits have been superseded by the much tighter limits described in Section \ref{['sec:analysis']}.
• Figure 5: The Fermilab accelerator complex, from Ref. accelerators.