Probing CP-violating Higgs-gauge Boson Couplings at Future Muon Collider

Abstract

We explore the sensitivity of future muon colliders to CP-violating interactions in the Higgs sector, specifically focusing on the process ${\mu }^{-}{\mu }^{+}\to h\overline{{\nu }_l}{\nu }_l\to b\bar{b}\overline{{\nu }_l}{\nu }_l$. Using a model-independent approach within the framework of the Standard Model Effective Field Theory (SMEFT), we analyze the contribution of dimension-six operators to Higgs-gauge boson couplings, emphasizing CP-violating effects. To simulate the process, all signal and background events are generated through MadGraph. The analysis provides 95\% confidence level limits on the relevant Wilson coefficients ${\tilde{c}}_{HB}$, ${\tilde{c}}_{HW}$, ${\tilde{c}}_{\gamma }$, with a comparative discussion of existing experimental and phenomenological constraints. Our best constraints on the ${\tilde{c}}_{HB}$, ${\tilde{c}}_{HW}$, ${\tilde{c}}_{\gamma }$ with an integrated luminosity of 10 ab${}^{-1}$ are $[-0.017428;0.018991]$, $[-0.002880;0.002586]$ and $[-0.010784;0.011381]$, respectively. In this context, this study highlights the capability of future muon collider experiments to probe new physics in the Higgs sector, potentially offering tighter constraints on CP-violating Higgs-gauge boson interactions than those provided by current colliders.

Comments: 19 pages, 10 figures