Discovering Strong Top Dynamics at the LHC

TL;DR

This paper investigates the phenomenology of top-pions and top-Higgs in models with strong top dynamics, assessing their compatibility with LHC observations, especially the 125 GeV state, and explores the implications for model parameters and signatures.

Contribution

It demonstrates that a neutral pseudoscalar top-pion can explain the 125 GeV diphoton signal, requiring specific isospin violation and dynamics similar to top seesaw models.

Findings

A top-pion can produce the observed diphoton rate.

Classic topcolor scenarios are disfavored without additional isospin violation.

The significance of initial ZZ and WW signals diminishes with more data.

Abstract

We analyze the phenomenology of the top-pion and top-Higgs states in models with strong top dynamics, and translate the present LHC searches for the Standard Model Higgs into bounds on these scalar states. We explore the possibility that the new state at a mass of approximately 125 GeV observed at the LHC is consistent with a neutral pseudoscalar top-pion state. We demonstrate that a neutral pseudoscalar top-pion can generate the diphoton signal at the observed rate. However, the region of model parameter space where this is the case does not correspond to classic topcolor-assisted technicolor scenarios with degenerate charged and neutral top-pions and a top-Higgs mass of order twice the top mass; rather, additional isospin violation would need to be present and the top dynamics would be more akin to that in top seesaw models. Moreover, the interpretation of the new state as a top-pion can be sustained only if the ZZ (four-lepton) and WW (two-lepton plus missing energy) signatures initially observed at the 3? level decline in significance as additional data is accrued.