New Physics Searches with Higgs-photon associated production at the Higgs Factory

TL;DR

This paper explores the potential of the e+e- to gamma h process at the Higgs factory as a sensitive probe for new physics, demonstrating its advantages over traditional methods through cross section calculations and bounds on effective operators.

Contribution

It introduces the gamma h production channel as a new, more sensitive method for detecting new physics at Higgs factories, with model-independent analysis and first-time bounds on operators.

Findings

Gamma h process has fewer degrees of freedom than Higgsstrahlung.

Gamma h is more sensitive to certain dimension-6 operators.

Potential to observe new physics effects at CEPC or FCC-ee.

Abstract

The Higgs factory is designed for precise measurement of Higgs characters and search for new physics. In this paper we propose that $e^+e^- \to \gamma h$ process could be a useful channel for new physics, which is normally expressed model independently by effective field theory. We calculate the cross section in both the Standard Model and effective field theory approach, and find that the new physics effects of $\gamma h$ have only two degrees of freedom, much fewer than the Higgsstrahlung process. This point could be used to reduce the degeneracies of Wilson coefficients. We also calculated for the first time the 2$\sigma$ bounds of $\gamma h$ at the Higgs factory, and prove that $\gamma h$ is more sensitive to some dimension-6 operators than the current experimental data. In the optimistic scenario new physics effects may be observed at the CEPC or FCC-ee after the first couple of years of their run.