Testing for observability of Higgs effective couplings in triphoton production at FCC-hh

Abstract

We investigate the potential of the $pp\to \gamma\gamma\gamma$ process to probe CP-conserving and CP-violating dimension-six operators of Higgs-gauge boson interactions in a model-independent Standard Model effective field theory framework at the center of mass energy of 100 TeV which is designed for the Future Circular hadron-hadron Collider. Signal events assuming the existence of anomalous Higgs boson couplings at $H\gamma\gamma$ and $HZ\gamma$ vertices and the relevant SM background events are generated in MadGraph, then passed through Pythia 8 for parton showering and Delphes to include detector effects. After detailed examination of kinematic variables, we use the invariant mass distribution of the two leading photons with optimized kinematic cuts to obtain constraints on the Wilson coefficients of dimension-six operators. We report that limits at 95\% confidence level on $\bar{c}_{\gamma}$ and $\tilde{c}_{\gamma}$ couplings with an integrated luminosity of 10 ab$^{-1}$ are [-0.0051; 0.0038] and [-0.0043; 0.0043] without systematic error, respectively.