An almost elementary Higgs: Theory and Practice

TL;DR

This paper explores models blending elementary and composite Higgs bosons, analyzing their theoretical structure and collider signatures, and provides bounds and search strategies for detecting new scalar states at the LHC.

Contribution

It classifies mixed Higgs models based on symmetries and studies their collider phenomenology, proposing new search channels and bounds for scalar particles.

Findings

Current LHC searches exclude certain heavy scalar states up to ~200 GeV.

Dedicated searches like $pp\to 3 \gamma W$ can significantly improve detection reach.

States mixing with the Higgs can be probed in $2b2\gamma$ final states.

Abstract

We study models that interpolate between an elementary and a composite Higgs boson. Such models, arising in theories with new vector-like fermions with electro-weak quantum numbers and charged under a confining gauge interaction, are entirely compatible with current data, with only weak bounds from flavor, CP-violation and precision tests. After classifying the models from the point of view of symmetries, we study their collider phenomenology at LHC. In the most relevant scenarios, bounds from present searches exclude heavy scalar isospin triplets and quintuplets up to $\sim 200\;$GeV and we show how dedicated searches of simple signals such as $pp\to 3 \gamma W$ could improve the reach by at least a factor of 2 with present data, reaching $O(1\;{\rm TeV})$ with higher integrated luminosities. States that mix with the SM Higgs can be tested in a variety of final states, such as $2b2\gamma$ searches relevant for double Higgs production.