Probing $HZ\gamma$ and $H\gamma\gamma$ anomalous couplings in the process of $e^+e^- \to H\gamma$

TL;DR

This paper investigates the potential to detect anomalous Higgs couplings in the process e+e- → Hγ, especially under a scenario where new physics effects cancel out in Higgs rare decays, using high-energy electron-positron colliders.

Contribution

It proposes a method to probe $HZ\gamma$ and $H\gamma\gamma$ anomalous couplings via e+e- collisions, even when new physics effects mimic standard model predictions in Higgs rare decays.

Findings

The faked-no-new-physics scenario can be fully tested at future colliders.

The process e+e- → Hγ is sensitive to anomalous Higgs couplings.

Proposed measurements can distinguish new physics effects from standard model predictions.

Abstract

Rare decay of the Higgs boson is a powerful tool to probe new physics beyond the standard model. The rare decays occur through quantum loops in which the standard model and new physics contributions might cancel each other out. We consider a faked-no-new-physics scenario that the new physics contributions are about minus two times the standard model contribution such that partial widths of Higgs boson rare decays are the same as the standard model predictions. We propose to measure the $HZ\gamma$ and $H\gamma\gamma$ anomalous couplings in the process of $e^+ e^- \to H\gamma$ that is strongly correlated to Higgs boson rare decays. We show that the faked-no-new-physics scenario can be fully probed at a high energy electron-positron collider.