Search for invisible decay of a Higgs boson produced at the CEPC

The existence of dark matter has been established in astrophysics. However, there is no candidate for DM in the Stand Model (SM). In SM, the Higgs boson can only decay invisibly via $Hrightarrow ZZ^ast rightarrow ubar{ u} ubar{ u}$ or DM, so any evidence of invisible Higgs decay that exceeds BR (H$rightarrow$inv.) will immediately point to a phenomenon that is beyond the standard model (BSM). In this paper, we report on the upper limit of BR (H$rightarrow$invisible) estimated for three channels, including two leptonic channels and one hadronic channel, under the assumption predicted by SM. With the SM ZH production rate, the upper limit of BR (H$rightarrow$inv.) could reach 0.24% at the 95% confidence level.