CP-violating Higgs-gauge boson couplings in $H\\nu \\bar{\\nu}$ production at three energy stages of CLIC

Abstract

A phenomenological study of CP-violating dimension-six operators via the $e^+e^-\\to\\nu \\bar{\\nu} H$ process is performed in a model-independent Standard Model effective field theory framework at all energy stages of CLIC using the updated baseline integrated luminosities. All signal and relevant background events are generated in MadGraph5$\\_$aMC@NLO and passed through PYTHIA 8 for parton showering and hadronization at parton level. Detector effects are considered via tuned CLIC detector cards in Delphes. Since we reconstruct the Higgs boson from a pair of b-jets, limits on CP-violating dimension-six couplings are obtained at three $b$-tagging working points: tight, medium and loose defined in the CLIC Delphes card for all three energy stages of CLIC. Our best 95 \\% C.L. limits at the loose working point (90 \\% b-tagging efficiency) on $\\tilde c_{HW}$ and $\\tilde c_{HB}$ are $[-7.0\\times10^{-3};7.0\\times10^{-3}]$ and $[-3.0\\times10^{-2};3.0\\times10^{-2}]$, respectively at the 3 TeV energy stage of CLIC with an integrated luminosity of 5.0 ab$^{-1}$. Considering a 0.3 \\% systematic uncertainty worsens the limits on these couplings by a factor of two.