Electroweak Chiral Lagrangian from TC2 Model with nontrivial TC fermion condensation and walking

TL;DR

This paper derives the electroweak chiral Lagrangian for a TC2 model with nontrivial fermion condensation and walking, revealing its phase structure, coefficient values, and effects on the S parameter.

Contribution

It provides a detailed calculation of the electroweak chiral Lagrangian coefficients for a specific TC2 model with walking and nontrivial condensation patterns, extending previous models.

Findings

Model features are similar to Lane's natural TC2 prototype.

Walking reduces the S parameter by half, maintaining an order of 2.

No upper bound limit on the Z' mass in this model.

Abstract

The electroweak chiral Lagrangian for the topcolor assisted technicolor model proposed by K. Lane, which uses nontrivial patterns of techniquark condensation and walking, was investigated in this study. We found that the features of the model are qualitatively similar to those of Lane's previous natural TC2 prototype model, but there is no limit on the upper bound of the Z' mass. We discuss the phase structure and possible walking behavior of the model. We obtained the values of all coefficients of the electroweak chiral Lagrangian up to an order of p4. We show that although the walking effect reduces the S parameter to half its original value, it maintains an order of 2. Moreover, a special hyper-charge arrangement is needed to achieve further reductions in its value.