Speaker
Description
We investigate the non-standard ν¯ν γγ couplings parameterized by dimension-seven operators through the process e^+ e^-→ν¯ν γ at the FCC-ee. A comprehensive Monte Carlo simulation is performed, where signal and relevant background events are generated within the MadGraph framework, incorporating the non-standard ν¯ν γγ interactions. Subsequent parton showering and hadronization are performed using Pythia, while detector effects are simulated using the IDEA detector card in Delphes. The projected sensitivity to ν¯ν γγ couplings is determined at a 5σ confidence level, both with and without a 5% systematic uncertainty at the FCC-ee. Notably, even when accounting for a 5% systematic uncertainty, the most stringent limit on anomalous ν¯ν γγ couplings obtained for a muon collider with √s=365 GeV and an integrated luminosity of L_int=1.5 ab-1 surpasses the upper bound derived from the analysis of the rare decay Z→γγν¯ν using LEP data by six orders of magnitude.