Signature of heavy sterile neutrinos at CEPC

TL;DR

This paper investigates the potential of the CEPC collider to detect heavy sterile neutrinos through their production and decay, analyzing backgrounds, sensitivities, and constraints from other experiments.

Contribution

It provides a detailed analysis of sterile neutrino production at CEPC, including single and degenerate pair production, and assesses the collider's sensitivity to sterile-active neutrino mixing.

Findings

CEPC has good sensitivity to sterile neutrino mixing around 100 GeV.

Backgrounds mainly from W pair production are manageable.

Constraints from neutrinoless double beta decay are considered.

Abstract

We study the production of heavy sterile neutrino $N$, $e^+ e^- \to N \nu({\bar \nu})$, 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 sterile neutrino with active neutrinos. We study the production of two degenerate heavy sterile neutrinos in a low energy see-saw model by taking into account the constraints on mixings of sterile neutrinos from the neutrino-less 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 sterile neutrino around 100 GeV.