Constraints on Anomalous Quartic Gauge Couplings via Electroweak Production of $\gamma \gamma jj$ at Future Proton-Proton Colliders

Abstract

The investigation of quartic gauge couplings provides a crucial test of the Standard Model and serves as a potential window into new physics at higher energy scales. Within the framework of Effective Field Theory, deviations from the SM can be parameterized through dimension-8 operators. In this study, we analyze the process $pp\to \gamma \gamma jj$ at the High-Luminosity Large Hadron Collider (HL-LHC) and the Future Circular Collider in hadron mode (FCC-hh) to probe the sensitivity to anomalous quartic gauge couplings (aQGCs), particularly $f_{T8}/{\Lambda }^4$ and $f_{T9}/{\Lambda }^4$. Monte Carlo simulations of signal and relevent backgrouds are performed using MadGraph for event generation, Pythia for parton showering and hadronization, and Delphes for detector simulation. A multivariate analysis based on Boosted Decision Trees is employed to optimize the signal-to-background discrimination, incorporating a comprehensive set of kinematic and reconstructed variables of the final state particles. Additionally, we evaluate unitarity-violating effects associated with dimension-8 operators by imposing energy cutoffs on the di-photon invariant mass. The expected exclusion and discovery significances are computed, accounting for systematic uncertainties to ensure a realistic assessment of collider reach. Our findings indicate that the FCC-hh offers significantly improved sensitivity compared to the HL-LHC and current experimental results by ATLAS, reinforcing its potential for probing aQGCs. Notably, even under a 10\% systematic uncertainty, our projected limits for FCC-hh at 95\% confidence level surpass the current best constraints reported by the ATLAS collaboration, highlighting the enhanced discovery prospects at future high-energy colliders.

Comments: 23 pages, 8 figures, Fixed typos in eq. (4)