Hypercharge-Universal Topcolor

TL;DR

This paper introduces a flavor-universal hypercharge Topcolor-assisted Technicolor model, analyzing its phenomenology, constraints, and compatibility with experimental data, showing it fits data as well as the Standard Model.

Contribution

It presents a novel flavor-universal hypercharge sector in Topcolor-assisted Technicolor models and evaluates its experimental viability compared to non-universal variants.

Findings

Precision electroweak measurements strongly constrain the model.

The model's fit to Z-pole and LEP2 data is comparable to the Standard Model.

Flavor non-universal hypercharge sectors are disfavored by data.

Abstract

We propose and discuss the phenomenology of a Topcolor-assisted Technicolor (TC2) model with a flavor-universal hypercharge sector. After discussing the symmetry breaking pattern and low-energy effective Lagrangian, we examine various experimental and theoretical constraints, finding that precision electroweak measurements yield the strongest bounds on the model. We perform a combined fit to all available $Z$-pole and LEP2 data and find that the goodness of fit for hypercharge-universal topcolor is comparable to that of the Standard Model. In contrast, TC2 models with a flavor non-universal hypercharge sectors are markedly disfavored by the data.