Global Analysis of General SU(2) x SU(2) x U(1) Models with Precision Data

TL;DR

This paper conducts a comprehensive global analysis of G(221) models with extended electroweak symmetry, deriving bounds on new heavy gauge bosons using precision electroweak data.

Contribution

It provides the first unified analysis of various G(221) models, quantifying the effects of new heavy gauge bosons on electroweak observables.

Findings

Lower bounds on Z' and W' masses established

Key electroweak observables sensitive to new physics identified

Consistent patterns in parameter constraints observed

Abstract

We present the results of a global analysis of a class of models with an extended electroweak gauge group of the form SU(2) x SU(2) x U(1), often denoted as G(221) models, which include as examples the left-right, the lepto-phobic, the hadro-phobic, the fermio-phobic, the un-unified, and the non-universal models. Using an effective Lagrangian approach, we compute the shifts to the coefficients in the electroweak Lagrangian due to the new heavy gauge bosons, and obtain the lower bounds on the masses of the Z' and W' bosons. The analysis of the electroweak parameter bounds reveals a consistent pattern of several key observables that are especially sensitive to the effects of new physics and thus dominate the overall shape of the respective parameter contours.