The Present and Future Status of Heavy Neutral Leptons

Abstract

The existence of non-zero neutrino masses points to the likely existence of multiple SM neutral fermions. When such states are heavy enough that they cannot be produced in oscillations, they are referred to as Heavy Neutral Leptons (HNLs). In this white paper we discuss the present experimental status of HNLs including colliders, beta decay, accelerators, as well as astrophysical and cosmological impacts. We discuss the importance of continuing to search for HNLs, and its potential impact on our understanding on key fundamental questions, and additionally we outline the future prospects for next-generation future experiments or upcoming accelerator run scenarios.

82 pages, 34 figures. Contribution to Snowmass 2021

References in corpus (138)

• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The Standard Model Higgs boson as the inflaton
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• Secluded WIMP Dark Matter
• Leptogenesis
• Massive neutrinos and cosmology
• Right-Handed Neutrinos at LHC and the Mechanism of Neutrino Mass Generation
• Matter and Antimatter in the Universe
• Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles
• Distinguishing seesaw models at LHC with multi-lepton signals
• From the trees to the forest: a review of radiative neutrino mass models
• Can sterile neutrinos be the dark matter?
• Low energy effects of neutrino masses
• Unitarity of the Leptonic Mixing Matrix
• How to find neutral leptons of the nuMSM?
• Dark-matter sterile neutrinos in models with a gauge singlet in the Higgs sector
• Left-Right Symmetry: from LHC to Neutrinoless Double Beta Decay
• Minimal Flavour Seesaw Models
• Non-unitarity of the leptonic mixing matrix: Present bounds and future sensitivities
• A possible symmetry of the $\nu$MSM
• General CP Violation in Minimal Left-Right Symmetric Model and Constraints on the Right-Handed Scale
• A lower bound on the mass of Dark Matter particles
• Cosmological constraints on exotic injection of electromagnetic energy
• Sterile Neutrinos as the Origin of Dark and Baryonic Matter
• The nuMSM, leptonic asymmetries, and properties of singlet fermions
• Heavy neutrino signals at large hadron colliders
• Opening a new window for warm dark matter
• Sterile neutrino dark matter as a consequence of nuMSM-induced lepton asymmetry
• Search for heavy neutrinos and W bosons with right-handed couplings in proton-proton collisions at sqrt(s) = 8 TeV
• How cold is cold dark matter? Small scales constraints from the flux power spectrum of the high-redshift Lyman-alpha forest
• Sterile Neutrinos
• Heavy Majorana Neutrinos in the Effective Lagrangian Description: Application to Hadron Colliders
• Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds
• Type-III see-saw at LHC
• Flavour Covariant Transport Equations: an Application to Resonant Leptogenesis
• Constraints from Ly-$\alpha$ forests on non-thermal dark matter including resonantly-produced sterile neutrinos
• Discovery of a 3.5 keV line in the Galactic Center and a Critical Look at the Origin of the Line Across Astronomical Targets
• Probing seesaw at LHC
• Determining the neutrino mass with Cyclotron Radiation Emission Spectroscopy - Project 8
• Right-handed neutrino magnetic moments
• Why should we care about the top quark Yukawa coupling?
• Search for Majorana neutrinos in $B^{-}\to {\pi }^{+}{\mu }^{-}{\mu }^{-}$ decays
• Heavy Majorana Neutrinos from $W\gamma$ Fusion at Hadron Colliders
• Measurement of the specific activity of Ar-39 in natural argon
• Thermal production of relativistic Majorana neutrinos: Strong enhancement by multiple soft scattering
• Search for Axionlike and Scalar Particles with the NA64 Experiment
• How well can cold-dark-matter substructures account for the observed radio flux-ratio anomalies?
• Left-Right Symmetry: from Majorana to Dirac
• Multilepton and Lepton Jet Probes of Sub-Weak-Scale Right-Handed Neutrinos
• Hitomi constraints on the 3.5 keV line in the Perseus galaxy cluster
• Double Bangs from New Physics in IceCube
• Search for heavy neutrinos and right-handed W bosons in events with two leptons and jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
• On the hadronic contribution to sterile neutrino production
• Constraints on Sterile Neutrinos in the MeV to GeV Mass Range
• Heavy Flavour Hadro-Production from Fixed-Target to Collider Energies
• Forensics of Subhalo-Stream Encounters: The Three Phases of Gap Growth
• Quantum Boltzmann Equations and Leptogenesis
• Neutrinophilic Non-Standard Interactions
• Baryon Asymmetry of the Universe in the NuMSM
• Resolution of puzzles from the LSND, KARMEN, and MiniBooNE experiments
• Search for heavy neutrinos in $K^{+}\to {\mu }^{+}{\nu }_H$ decays
• Neutrino Jets from High-Mass $W_R$ Gauge Bosons in TeV-Scale Left-Right Symmetric Models
• Neutrinoless double beta decay in chiral effective field theory: lepton number violation at dimension seven
• Gaps in globular cluster streams: giant molecular clouds can cause them too
• Resonant CP Violation due to Heavy Neutrinos at the LHC
• Mixing of Active and Sterile Neutrinos
• Search for heavy neutral lepton production in $K^{+}$ decays
• Explaining $(g-2{)}_{\mu ,e}$, the KOTO anomaly and the MiniBooNE excess in an extended Higgs model with sterile neutrinos
• Strong P invariance, neutron EDM and minimal Left-Right parity at LHC
• Search for heavy neutral lepton production in $K^{+}$ decays to positrons
• Where do the 3.5 keV photons come from? A morphological study of the Galactic Center and of Perseus
• Sterile Neutrinos in Light of Recent Cosmological and Oscillation Data: a Multi-Flavor Scheme Approach
• A Dark Matter Progenitor: Light Vector Boson Decay into (Sterile) Neutrinos
• Revisiting the Dark Photon Explanation of the Muon Anomalous Magnetic Moment
• Lepton Number Violation and W' Chiral Couplings at the LHC
• A Simple Motivated Completion of the Standard Model below the Planck Scale: Axions and Right-Handed Neutrinos
• Supernova bound on keV-mass sterile neutrinos reexamined
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• Collisional production of sterile neutrinos via secret interactions and cosmological implications
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• $N_{\mathrm{eff}}$ in low-scale seesaw models versus the lightest neutrino mass
• On Resonant Leptogenesis
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• $Z^{\prime }$ discovery potential at the LHC in the minimal $B-L$ extension of the Standard Model
• Decaying dark matter search with NuSTAR deep sky observations
• Fundamental physics with the Hubble Frontier Fields: constraining Dark Matter models with the abundance of extremely faint and distant galaxies
• Search for heavy neutrinos and W[R] bosons with right-handed couplings in a left-right symmetric model in pp collisions at sqrt(s) = 7 TeV
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• Dark sector origin of the KOTO and MiniBooNE anomalies
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• Sterile neutrino oscillations in core-collapse supernovae
• Electroweak vacuum stability in presence of singlet scalar dark matter in TeV scale seesaw models
• Searches for Lepton Number Violation and Resonances in $K^{\pm }\to \pi \mu \mu$ Decays
• Strong Washout Approximation to Resonant Leptogenesis
• Higgs Boson Mass Bounds in the Standard Model with Type III and Type I Seesaw
• Majorana Neutrinos in Same-Sign $W^{\pm }{W}^{\pm }$ Scattering at the LHC: Breaking the TeV Barrier
• The broadening of Lyman-alpha forest absorption lines
• Corrigendum to "Flavour Covariant Transport Equations: an Application to Resonant Leptogenesis"
• Nearly degenerate heavy sterile neutrinos in cascade decay: mixing and oscillations
• The MicroBooNE Experiment, the NuMI Absorber, and Heavy Neutral Leptons
• New constraints on tau-coupled Heavy Neutral Leptons with masses $m_N=280-970$ MeV
• Sterile neutrino dark matter via GeV-scale leptogenesis?
• Heavy neutrinos from gluon fusion
• Search for heavy neutral leptons in $W^{+}\to {\mu }^{+}{\mu }^{\pm }\text{jet}$ decays
• Resonant production of the sterile neutrino dark matter and fine-tunings in the [nu]MSM
• Dark Matter Relic Abundance and Light Sterile Neutrinos
• Freeze-out of baryon number in low-scale leptogenesis
• The XMM Cluster Survey: new evidence for the 3.5 keV feature in clusters is inconsistent with a dark matter origin
• Revisiting the LHC reach in the displaced region of the minimal left-right symmetric model
• Kinetic equations for sterile neutrinos from thermal fluctuations
• Dark Matter-Neutrino Interconversion at COHERENT, Direct Detection, and the Early Universe
• Heavy Neutrino-Antineutrino Oscillations in Quantum Field Theory
• Z-Boson Decays into Majorana or Dirac (Heavy) Neutrinos
• Measurements of $\mu \to 3e$ Decay with Polarised Muons as a Probe of New Physics
• Supernova Bounds on keV-mass Sterile Neutrinos
• Testing extensions to LCDM on small scales with forthcoming cosmic shear surveys
• Relativistic Cyclotron Radiation Detection of Tritium Decay Electrons as a New Technique for Measuring the Neutrino Mass
• Hunt for rare processes and long-lived particles at FCC-ee

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• Composite Dark Matter and Neutrino Masses from a Light Hidden Sector
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• Low scale leptogenesis under neutrino $\mu$-$\tau$ reflection symmetry
• Relaxing Limits from Big Bang Nucleosynthesis on Heavy Neutral Leptons with Axion-like Particles
• Sensitivity prospects for lepton-trijet signals in the $\nu$SMEFT at the LHeC
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• Workshop summary -- Kaons@CERN 2023
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