Probing Higgs $CP$ properties at the CEPC

TL;DR

This paper investigates the potential of the CEPC collider to measure the CP properties of the Higgs boson, providing constraints on CP-violating parameters using simulated collision data.

Contribution

It presents the first detailed analysis of Higgs CP property measurements at the CEPC, including projected constraints on CP-violating parameters with specific decay channels.

Findings

Constraints on $ ilde{c}_{Z o ext{gamma}}$ between -0.30 and 0.27

Constraints on $ ilde{c}_{Z Z}$ between -0.06 and 0.06

Demonstrates the CEPC's potential for probing Higgs CP properties

Abstract

In the Circular Electron Positron Collider (CEPC), a measurement of the Higgs CP mixing through $e^{+} e^{-} \rightarrow Z H \rightarrow l^{+} l^{-}(e^{+} e^{-} /\mu^{+} \mu^{-}) H(\rightarrow b \bar{b} / c \bar{c} / g g)$ process is presented, with $5.6\ \mbox{ab}^{-1}$ $e^{+} e^{-}$ collision data at the center-of-mass energy of $240\ \mathrm{GeV}$. In this study, the CP-violating parameter $\tilde{c}_{Z \gamma}$ is constrained between the region of $ -0.30$ and $0.27$ and $\tilde{c}_{Z Z}$ between $-0.06$ and $0.06$ at $68\%$ confidence level. This study demonstrates the great potential of probing Higgs $CP$ properties at the CEPC.