Probing neutrino compositeness with invisible and displaced signals
- 1University of Florence
- 2Perimeter Institute for Theoretical Physics
- 3Galileo Galilei Institute for Theoretical Physics
Abstract
We explore the possibility that neutrinos couple to an interacting sterile sector, providing a novel portal that generalizes the heavy neutral lepton portal to a composite setting. For a low confinement scale, high-energy neutrino beams can disintegrate into collimated sprays of hidden states, referred to as “dark jets”. This dynamics gives rise to two characteristic signatures in high energy neutrino beams. First, long-lived dark resonances can enhance the neutral-current to charged-current ratio. Second, shorter-lived dark states produced in neutrino neutral currents can produce single or multiple displaced vertices and even emerging jets, depending on the kinematics. These signals probe regions of parameter space beyond existing constraints from meson, electroweak, and Higgs decays, as well as from searches for displaced decays at beam dump experiments. We study these phenomena within broad classes of ultraviolet completions and identify scenarios in which high-energy neutrino beams provide leading sensitivity to neutrino compositeness. Such scenarios generically induce higher-dimensional contact interactions, which we classify and study alongside their complementary experimental signatures. Finally, we outline an experimental program spanning both the intensity and energy frontiers. Near-term neutrino facilities (DUNE, FPF) and running flavor experiments (LHCb, Belle II) can probe neutrino compositeness through neutrino disintegration into dark jets and displaced B-meson decays. Future colliders — particularly the Future Circular Collider (FCC-ee) — will ultimately provide the strongest sensitivity to the compositeness scale via displaced Z decays.
Related
- Displaced Signals from Long-lived Particles in Neutrinoless Double Beta Decay
- Probing νSMEFT at Belle II with displaced dilepton vertices
- Probing Massive Invisible Dark Photons in Higgs Decays via Gluon--Gluon Fusion at ATLAS Run 3
- Probing the neutrino mass through semileptonic decays
- Solar Neutrino Signals and Capture-Annihilation Equilibrium of SU(5) Neutralino Dark Matter
BibTeX
@article{borrello2026probing,
title = {{Probing neutrino compositeness with invisible and displaced signals}},
author = {Matteo Borrello and Marco Costa and Diego Redigolo and Michele Tammaro},
journal = {Journal of High Energy Physics},
year = {2026},
month = oct,
doi = {10.1007/jhep10(2026)252},
url = {https://link.springer.com/article/10.1007/JHEP10(2026)252},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Probing neutrino compositeness with invisible and displaced signals
AU - Matteo Borrello
AU - Marco Costa
AU - Diego Redigolo
AU - Michele Tammaro
PY - 2026
DA - 2026/10/26
JO - Journal of High Energy Physics
DO - 10.1007/jhep10(2026)252
UR - https://link.springer.com/article/10.1007/JHEP10(2026)252
AB - We explore the possibility that neutrinos couple to an interacting sterile sector, providing a novel portal that generalizes the heavy neutral lepton portal to a composite setting. For a low confinement scale, high-energy neutrino beams can disintegrate into collimated sprays of hidden states, referred to as “dark jets”. This dynamics gives rise to two characteristic signatures in high energy neutrino beams. First, long-lived dark resonances can enhance the neutral-current to charged-current ratio. Second, shorter-lived dark states produced in neutrino neutral currents can produce single or multiple displaced vertices and even emerging jets, depending on the kinematics. These signals probe regions of parameter space beyond existing constraints from meson, electroweak, and Higgs decays, as well as from searches for displaced decays at beam dump experiments. We study these phenomena within broad classes of ultraviolet completions and identify scenarios in which high-energy neutrino beams provide leading sensitivity to neutrino compositeness. Such scenarios generically induce higher-dimensional contact interactions, which we classify and study alongside their complementary experimental signatures. Finally, we outline an experimental program spanning both the intensity and energy frontiers. Near-term neutrino facilities (DUNE, FPF) and running flavor experiments (LHCb, Belle II) can probe neutrino compositeness through neutrino disintegration into dark jets and displaced B-meson decays. Future colliders — particularly the Future Circular Collider (FCC-ee) — will ultimately provide the strongest sensitivity to the compositeness scale via displaced Z decays.
SN - 1029-8479
ER -