Monojet search for heavy neutrinos at future $Z$-factories

Abstract

The existence of heavy neutrinos is the most prominent feature of type-I seesaw-like mechanisms, which naturally explain tiny masses of observed neutrinos. Various experiments have been conducted to search for heavy neutrinos, with meson decays sensitive to heavy neutrinos lighter than $B$ mesons and high energy collider experiments sensitive to the ones with masses larger than $\mathcal{O}(0.1)$ TeV. In between, there is a mass gap uncovered by these two kinds of experiments, and by this work, we investigate the 3-15 GeV neutrino searches at future $Z$-factories via the process $e^{-}{e}^{+}\to Z\to \nu N\to \nu \ell \bar{q}{q}^{\prime }$ with $\ell =e,\mu$. Based on the simulation of signal and background events, we find that the signals appear as monojet events owning to the large Lorentz boost of the heavy neutrinos. Furthermore, the substructures of such monojet are essential to reconstruct the signal and suppress the background. The upper bounds on the cross section of the signal process and the mixing parameter ${|V_{\ell N}|}^2$ are obtained. Compared with other experiments, the monojet method at future $Z$-factories will be able to fill the gap around this mass range.

References in corpus (10)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• Distinguishing seesaw models at LHC with multi-lepton signals
• Neutrinoless Double-Beta Decay: a Probe of Physics Beyond the Standard Model
• Heavy Majorana Neutrinos from $W\gamma$ Fusion at Hadron Colliders
• Constraints on Sterile Neutrinos in the MeV to GeV Mass Range
• Indirect searches for sterile neutrinos at a high-luminosity Z-factory
• Lepton flavor violating decays of vector quarkonia and of the $Z$ boson
• Study Majorana Neutrino Contribution to B-meson Semi-leptonic Rare Decays
• Z-Boson Decays into Majorana or Dirac (Heavy) Neutrinos