Electroweak Limits on General New Vector Bosons

TL;DR

This paper investigates how general new vector bosons, constrained by Standard Model symmetries, affect electroweak precision measurements, providing limits and exploring their implications for Higgs mass and anomalies.

Contribution

It develops a comprehensive effective Lagrangian framework for generic vector bosons and derives electroweak constraints, including effects of multiple vectors and nonuniversal couplings.

Findings

Sets bounds on vector boson couplings from electroweak data

Shows multiple vectors can explain certain anomalies

Analyzes impact on Higgs mass predictions

Abstract

We study extensions of the Standard Model with general new vector bosons. The full Standard Model gauge symmetry is used to classify the extra vectors and constrain their couplings. We derive the corresponding effective Lagrangian, valid at energies lower than the mass of the extra vectors, and use it to extract limits from electroweak precision observables, including LEP 2 data. We consider both universal and nonuniversal couplings to fermions. We study the interplay of several extra vectors, which can have the effect of opening new regions in parameter space. In particular, it allows to explain the anomaly in the bottom forward-backward asymmetry with perturbative couplings. Finally, we analyze quantitatively the implications for the Higgs mass.