Model-independent study on the anomalous $ZZ\gamma$ and $Z\gamma\gamma$ couplings at the future muon collider

TL;DR

This paper assesses the sensitivity of a future 3 TeV muon collider to anomalous neutral gauge couplings involving Z and gamma bosons, using detailed simulations and considering systematic uncertainties.

Contribution

It provides the first comprehensive sensitivity analysis of the muon collider for these specific anomalous couplings, including systematic effects and comparison with other collider projections.

Findings

Achieves sensitivities 5-15 times better than current experiments.

Provides bounds comparable to future proton-proton colliders.

Shows future e+e- colliders could improve bounds by a factor of 2.

Abstract

In this study, we investigate the potential of $\mu^{-} \mu^{+}\to Z\gamma \to \nu\bar{\nu}\gamma$ process at the future muon collider with a center-of-mass energy of 3 TeV to examine the anomalous $ZZ\gamma$ and $Z\gamma\gamma$ neutral triple gauge couplings defining $CP$-conserving $C_{\widetilde{B}W}/{\Lambda^4}$ coupling and three $CP$-violating $C_{BB}/{\Lambda^4}$, $C_{BW}/{\Lambda^4}$, $C_{WW}/{\Lambda^4}$ couplings. All signal and relevant background events are generated in MadGraph and passed through Pythia for parton showering and hadronization. Detector effects are also considered via tuned muon detector cards in Delphes. The effects of systematic uncertainties of $0\%$, $3\%$ and $5\%$ on the sensitivities are studied. The best sensitivities obtained from the process $\mu^{-} \mu^{+}\to Z\gamma \to \nu\bar{\nu}\gamma$ are $[-6.53;6.64]\times10^{-2}$ TeV$^{-4}$ on $CP$-conserving $C_{\widetilde{B}W}/{\Lambda^4}$ coupling and $[-2.47;2.47]\times10^{-2}$ TeV$^{-4}$, $[-8.46;8.46]\times10^{-2}$ TeV$^{-4}$ and $[-2.20;2.20]\times10^{-1}$ TeV$^{-4}$ on $CP$-conserving $C_{BB}/{\Lambda^4}$, $C_{BW}/{\Lambda^4}$, $C_{WW}/{\Lambda^4}$ couplings , respectively. Our obtained results on the anomalous neutral gauge couplings set more stringent sensitivity, ranging between 5 and 15 times than the current experimental results while slightly better than the phenomenological studies at future pp colliders such as the HL-LHC, the HE-LHC and the FCC-hh, respectively. On the other hand, we can see that the bounds on the anomalous neutral gauge couplings expected to be obtained for the future $e^{-}e^{+}$ colliders such as the CLIC are roughly 2 times better than our results.