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Quantum collider probes of the fermionic Higgs portal

by Ulrich Haisch, Maximilian Ruhdorfer, Konstantin Schmid, Andreas Weiler

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Submission summary

Authors (as registered SciPost users): Ulrich Haisch
Submission information
Preprint Link: scipost_202312_00002v3  (pdf)
Date accepted: 2024-04-03
Date submitted: 2024-03-14 19:25
Submitted by: Haisch, Ulrich
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
  • High-Energy Physics - Phenomenology
Approach: Phenomenological


We explore the sensitivity of future hadron colliders to constrain the fermionic Higgs portal, with a focus on scenarios where the new fermions cannot be directly observed in exotic Higgs decays. This portal emerges in various models including twin-Higgs scenarios and dark matter models, posing significant challenges for collider tests. Working in an effective field theory (EFT), we determine the reach of the high-luminosity option of the Large Hadron Collider (HL-LHC), the high-energy upgrade of the LHC (HE-LHC) and a proposed Future Circular Collider (FCC) in probing the fermionic Higgs portal through off-shell and double-Higgs production. Notably, we find that quantum-enhanced indirect probes offer a better sensitivity than other direct Higgs measurements. We argue that this finding is valid in a wide class of ultraviolet realisations of the EFT. Our study presents a roadmap of a multifaceted search strategy for exploring the fermionic Higgs portal at forthcoming hadron machines.

Author comments upon resubmission

We thank the referees for their additional comments. Following the advice of one of the referees, we have now studied the effect of non-zero initial conditions of the Wilson coefficients of the operators $Q_6$ and $Q_{H \Box}$ in off-shell and double-Higgs production. This study is detailed in a new Appendix D. We have also amended the abstract as recommended by this referee. During the revision process, we identified a minor mistake in our Monte Carlo implementation of double-Higgs production. We have rectified this mistake and regenerated all relevant plots, updating the text accordingly. All changes and additions are indicated in red in the resubmitted PDF file. We hope that with these revisions, our manuscript will meet the criteria for publication in SciPost.

Published as SciPost Phys. 16, 112 (2024)

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