We study the production of heavy sterile neutrino $N$, $e^{+}{e}^{-}\to N\nu (\overline{\nu })$, at the Circular Electron Positron Collider (CEPC) and its $ljj$ signal in its decay to three charged fermions. We study background events for this process which are mainly events coming from W pair production. We study the production of a single heavy sterile neutrino and the sensitivity of CEPC to the mixing of the sterile neutrino with active neutrinos. We study the production of two degenerate heavy sterile neutrinos in a low energy seesaw model by taking into account the constraints on mixings of sterile neutrinos from the neutrinoless double $\beta$ decay experiment and the masses and mixings of active neutrinos. We show that CEPC under proposal has a good sensitivity to the mixing of sterile neutrinos with active neutrinos for a mass of a sterile neutrino around 100 GeV.

• Received 31 October 2017

DOI:https://doi.org/10.1103/PhysRevD.97.055005

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Published by the American Physical Society