Discovering heavy neutrino-antineutrino oscillations at the Z-pole

Abstract Collider-testable type I seesaw extensions of the Standard Model are generally protected by an approximate lepton number (LN) symmetry. Consequently, they predict pseudo-Dirac heavy neutral leptons (HNLs) composed of two nearly degenerate Majorana fields. The interference between the two ma...

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Main Authors: Stefan Antusch, Jan Hajer, Bruno M. S. Oliveira
Format: Article
Language:English
Published: SpringerOpen 2024-11-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP11(2024)102
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author Stefan Antusch
Jan Hajer
Bruno M. S. Oliveira
author_facet Stefan Antusch
Jan Hajer
Bruno M. S. Oliveira
author_sort Stefan Antusch
collection DOAJ
description Abstract Collider-testable type I seesaw extensions of the Standard Model are generally protected by an approximate lepton number (LN) symmetry. Consequently, they predict pseudo-Dirac heavy neutral leptons (HNLs) composed of two nearly degenerate Majorana fields. The interference between the two mass eigenstates can induce heavy neutrino-antineutrino oscillations ( N N ¯ Os $$ N\overline{N}\textrm{Os} $$ ) leading to observable lepton number violation (LNV), even though the LN symmetry is approximately conserved. These N N ¯ Os $$ N\overline{N}\textrm{Os} $$ could be resolved in long-lived HNL searches at collider experiments, such as the proposed Future Circular e + e − Collider (FCC-ee) or Circular Electron Positron Collider (CEPC). However, during their Z-pole runs, the LN carried away by the light (anti)neutrinos produced alongside the HNLs prevents LNV from being observed directly. Nevertheless, N N ¯ Os $$ N\overline{N}\textrm{Os} $$ materialise as oscillating signatures in final state distributions. We discuss and compare a selection of such oscillating observables, and perform a Monte Carlo simulation to assess the parameter space in which N N ¯ Os $$ N\overline{N}\textrm{Os} $$ could be resolved.
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spelling doaj-art-2455736ace984119bd6495d7371cb94c2024-12-08T12:10:17ZengSpringerOpenJournal of High Energy Physics1029-84792024-11-0120241112810.1007/JHEP11(2024)102Discovering heavy neutrino-antineutrino oscillations at the Z-poleStefan Antusch0Jan Hajer1Bruno M. S. Oliveira2Departement Physik, Universität BaselCentro de Física Teórica de Partículas (CFTP), Instituto Superior Técnico (IST), Universidade de LisboaCentro de Física Teórica de Partículas (CFTP), Instituto Superior Técnico (IST), Universidade de LisboaAbstract Collider-testable type I seesaw extensions of the Standard Model are generally protected by an approximate lepton number (LN) symmetry. Consequently, they predict pseudo-Dirac heavy neutral leptons (HNLs) composed of two nearly degenerate Majorana fields. The interference between the two mass eigenstates can induce heavy neutrino-antineutrino oscillations ( N N ¯ Os $$ N\overline{N}\textrm{Os} $$ ) leading to observable lepton number violation (LNV), even though the LN symmetry is approximately conserved. These N N ¯ Os $$ N\overline{N}\textrm{Os} $$ could be resolved in long-lived HNL searches at collider experiments, such as the proposed Future Circular e + e − Collider (FCC-ee) or Circular Electron Positron Collider (CEPC). However, during their Z-pole runs, the LN carried away by the light (anti)neutrinos produced alongside the HNLs prevents LNV from being observed directly. Nevertheless, N N ¯ Os $$ N\overline{N}\textrm{Os} $$ materialise as oscillating signatures in final state distributions. We discuss and compare a selection of such oscillating observables, and perform a Monte Carlo simulation to assess the parameter space in which N N ¯ Os $$ N\overline{N}\textrm{Os} $$ could be resolved.https://doi.org/10.1007/JHEP11(2024)102Sterile or Heavy NeutrinosNew Light ParticlesSpecific BSM Phenomenology
spellingShingle Stefan Antusch
Jan Hajer
Bruno M. S. Oliveira
Discovering heavy neutrino-antineutrino oscillations at the Z-pole
Journal of High Energy Physics
Sterile or Heavy Neutrinos
New Light Particles
Specific BSM Phenomenology
title Discovering heavy neutrino-antineutrino oscillations at the Z-pole
title_full Discovering heavy neutrino-antineutrino oscillations at the Z-pole
title_fullStr Discovering heavy neutrino-antineutrino oscillations at the Z-pole
title_full_unstemmed Discovering heavy neutrino-antineutrino oscillations at the Z-pole
title_short Discovering heavy neutrino-antineutrino oscillations at the Z-pole
title_sort discovering heavy neutrino antineutrino oscillations at the z pole
topic Sterile or Heavy Neutrinos
New Light Particles
Specific BSM Phenomenology
url https://doi.org/10.1007/JHEP11(2024)102
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AT janhajer discoveringheavyneutrinoantineutrinooscillationsatthezpole
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