Z-Boson Decays into Majorana or Dirac (Heavy) Neutrinos
arXiv:2105.06576 · doi:10.1103/PhysRevD.104.055027
Abstract
We computed the kinematics of Z-boson decay into a heavy-light neutrino pair when the Z-boson is produced at rest in electron-positron collisions, including the subsequent decay of the heavy neutrino into a visible final state containing a charged-lepton. We concentrated on heavy-neutrino masses of order dozens of GeV and the issue of addressing the nature of the neutrinos - Dirac fermions or Majorana fermions. We find that while it is not possible to tell the nature of the heavy and light neutrinos on an event-by-event basis, the nature of the neutrinos can nonetheless be inferred given a large-enough sample of heavy-light neutrino pairs. We identify two observables sensitive to the nature of neutrinos. One is the forward-backward asymmetry of the daughter-charged-leptons. This asymmetry is exactly zero if the neutrinos are Majorana fermions and is non-zero (and opposite) for positively- and negatively-charged daughter-leptons if the neutrinos are Dirac fermions. The other observable is the polarization of the heavy neutrino, imprinted in the laboratory-frame energy distribution of the daughter-charged-leptons. Dirac neutrinos and antineutrinos produced in electron-positron collisions at the Z-pole are strongly polarized while Majorana neutrinos are at most as polarized as the -bosons.
arXiv comment12 pages, 7 figures, references added in v2, results and conclusions unchanged
References in corpus (39)
- Neutrinoless Double-Beta Decay: Status and Prospects
- Neutrino Masses from Large Extra Dimensions
- Light Neutrinos without Heavy Mass Scales: A Higher-Dimensional Seesaw Mechanism
- Long-Lived Particles at the Energy Frontier: The MATHUSLA Physics Case
- FASER's Physics Reach for Long-Lived Particles
- How to find neutral leptons of the nuMSM?
- Global constraints on heavy neutrino mixing
- Probing Large Extra Dimensions with Neutrinos
- Phenomenology of GeV-scale Heavy Neutral Leptons
- Lepton Flavor and Number Conservation, and Physics Beyond the Standard Model
- Neutrinoless double beta decay versus other probes of heavy sterile neutrinos
- Double Bangs from New Physics in IceCube
- Displaced vertex searches for sterile neutrinos at future lepton colliders
- Constraints on Sterile Neutrinos in the MeV to GeV Mass Range
- Combining Experimental and Cosmological Constraints on Heavy Neutrinos
- Search for heavy neutrinos with the T2K near detector ND280
- Testing the low scale seesaw and leptogenesis
- Searches for Decays of New Particles in the DUNE Multi-Purpose Near Detector
- Heavy Neutral Leptons from low-scale seesaws at the DUNE Near Detector
- Addressing the Majorana vs. Dirac Question with Neutrino Decays
- GeV-scale neutrinos: interactions with mesons and DUNE sensitivity
- Long-lived Sterile Neutrinos at the LHC in Effective Field Theory
- MeV-scale sterile neutrino decays at the Fermilab Short-Baseline Neutrino program
- Improved Constraints on Sterile Neutrinos in the MeV to GeV Mass Range
- Extended Black Box Theorem for Lepton Number and Flavor Violating processes
- Dark Scalars and Heavy Neutral Leptons at DarkQuest
- l W nu production at CLIC: a window to TeV scale non-decoupled neutrinos
- On DUNE prospects in the search for sterile neutrinos
- On Lepton Number Violation in Heavy Neutrino Decays at Colliders
- Search for heavy neutral leptons decaying into muon-pion pairs in the MicroBooNE detector
- Dark Matter and Neutrino Mass from the Smallest Non-Abelian Chiral Dark Sector
- Majorana vs Pseudo-Dirac Neutrinos at the ILC
- Heavy neutrino search in accelerator-based experiments
- Heavy Neutral Leptons from kaon decays in the SHiP experiment
- Searches for Atmospheric Long-Lived Particles
- Three-Body Decays of Heavy Dirac and Majorana Fermions
- Heavy neutrino searches at future -factories
- Search for sterile neutrinos decaying into pions at the LHC
- Signature of heavy sterile neutrinos at CEPC
Cited by in corpus (11)
- The Present and Future Status of Heavy Neutral Leptons
- Mapping the viable parameter space for testable leptogenesis
- Searches for Long-Lived Particles at the Future FCC-ee
- New Benchmark Models for Heavy Neutral Lepton Searches
- Distinguishing Dirac and Majorana Heavy Neutrinos at Lepton Colliders
- Monojet search for heavy neutrinos at future -factories
- New Physics Search at the CEPC: a General Perspective
- Heavy Neutrino Searches via Same-sign Lepton Pairs at the Higgs Factory
- New Particles at the Z-Pole: Tera-Z factories as discovery and precision machines
- Constraints on Heavy Neutral Leptons interacting with a singlet scalar
- Characterizing Heavy Neutral Fermions via their Decays