Exotic Quarks in Twin Higgs Models

TL;DR

This paper explores exotic quarks in Twin Higgs models, focusing on their collider signatures, decay modes, and potential to probe the model up to multi-TeV energies at current and future colliders.

Contribution

It introduces the phenomenology of exotic quarks in non-supersymmetric Twin Higgs completions, including their production, decay channels, and distinctive displaced vertex signals.

Findings

Exotic quarks could be produced up to ~2.5 TeV at the LHC.

Displaced vertex signals from twin sector decays are detectable.

Future colliders could probe exotic quarks beyond 10 TeV.

Abstract

The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ~ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of the model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. Depending on the details of the twin sector, the exotic quarks may be probed up to ~ 2.5 TeV at the LHC and beyond 10 TeV at a future 100 TeV collider, providing a strong test of this class of ultraviolet completions.