The small but non-zero neutrino masses have remained

The gap

Evidence profile

Sourced from the stated research gap and stated challenges and future work and future-work section and abstract of the source papers, classified as general, drawn from work published between 2018 and 2026, spanning 7 journals. Those papers have been cited 276 times in total.

Supporting evidence — 8 representative gaps

• Gravity-assisted neutrino masses (2026) · Physics Letters B · doi

  The small but non-zero neutrino masses have remained a puzzle since the discovery of neutrino oscillations. Earlier attempts to exploit gravity-induced effects in neutrino masses were explored but ruled out by the KamLAND measurement of ∆m^2 21.

  generalstated research gap
  Keywords: small non-zero neutrino masses have remained puzzle since
• Neutrino oscillation in dark matter with L μ − L τ (2026) · Communications in Theoretical Physics · doi

  The study of dark matter is challenging due to its unknown properties. The Lμ-Lτ model is a complex gauge theory that requires careful analysis. The neutrino oscillation behavior in the dark halo is difficult to understand due to the presence of multiple interactions.

  generalstated challenges
  Keywords: study dark matter challenging due unknown properties model
• Gravity-assisted neutrino masses (2026) · Physics Letters B · doi

  In this Letter, we have introduced a novel modelbuilding framework in which the observed smallness of light neutrino masses arises “gravity-assisted”. While neutrino masses generated by a Planck-suppressed Weinberg operator are expected to be too small, and the standard type-I seesaw mechanism with order one couplings points to high-scale neutrino mass generation far above observational capabilities, the “gravity-assisted” scheme opens up new possibilities for constructing “low-scale” neutrino mass generation models, where light neutrino masses are “symmetry protected” and therefore technically natural. No small model parameters or cancellations are required in order to arrive at models that explain the small light neutrino masses while being within reach of the (HL-)LHC and future colliders and testable by precision experiments (e.g. on cLFV). Gravity-assisted neutrino masses arise in the presence of a global symmetry that is spontaneously broken at an intermediate scale between the electroweak and Planck leaving a remnant discrete symmetry that forscales, bids light neutrino masses. After spontaneous symmetry breaking, masses and mixing with active neutrinos are generated for the HNLs, potentially suppressed by powers of ⟨ϕ⟩ /Λ. Nevertheless, light neutrinos remain massless due to the residual discrete symmetry, and pairs of right-chiral neutrinos form (at this level exact) heavy Dirac states. Light neutrino masses finally arise through gravity, when the residual symmetry is broken by Plancksuppressed effective operators. The result is small light neutrino masses and pseudo-Dirac pairs of heavy neutrinos with masses that can lie within the reach of future collider experiments, far below the usually expected high seesaw scale. We described the proposed new scheme explicitly for the case of 2 HNLs and a global U(1) symmetry broken spontaneously to a Z3 subgroup. It leads to a plethora of new models with expected rich phenomenology that depends on the symmetry assignments. We illustrated “gravity-assisted” neutrino mass generation and its phenomenological implications for collider searches in a simple benchmark realisation, leaving a more comprehensive exploration of the model class and its extensions for future work. In addition to predictions for future collider 5 searches and precision tests such as cLFV, which may allow to test and distinguish specific model realisations, various cosmological consequences also offer interesting discovery potential. For example, the breaking of the U(1) symmetry, spontaneously as well as explicitly by gravity, leads to a Pseudo-Nambu Goldstone boson with mass linked to MR. This breaking may additionally induce networks of hybrid topological defects composed of cosmic strings and domain walls, which may generate a testable contribution to the stochastic gravitational wave background.

  generalfuture workevidence 5/5
  Keywords: neutrino masses symmetry light gravity model assisted small scale mass models planck suppressed expected generation
• Signatures and probes of mirror mesons at colliders (2026) · The European Physical Journal Special Topics · doi

  The Standard Model is incomplete and cannot explain non-vanishing neutrino masses - The nature of neutrino masses is one of the most puzzling questions in particle physics - The EW-νR model attempts to fill this gap by providing a solution to the problem of non-vanishing neutrino masses

  generalstated research gapevidence 5/5
  Keywords: standard model incomplete cannot explain non-vanishing neutrino masses
• Effects of gravitational lensing on neutrino oscillation in Hu-Sawicki f(R) gravity (2026) · International Journal of Modern Physics A · doi

  Future high precision measurements of lensed neutrinos from compact astrophysical objects could help test modified gravity models and constrain neutrino parameters. The exploration of neutrino oscillations in other modified gravity models. The inclusion of experimental data to validate the theoretical results.

  generalfuture-work sectionevidence 5/5
  Keywords: future high precision measurements lensed neutrinos compact astrophysical
• Leptogenesis and neutrino masses via pseudo-Dirac gauginos (2026) · Physical Review D · doi

  Further study of the model's phenomenology at future colliders. Investigation of the model's implications for neutrino masses and mixing. Analysis of the model's compatibility with other areas of particle physics, such as dark matter and the Higgs sector.

  generalfuture-work sectionevidence 5/5
  Keywords: further study model phenomenology future colliders investigation implications
• NuSTEC  White Paper: Status and challenges of neutrino–nucleus scattering (2018) · Progress in Particle and Nuclear Physics · cited 276× · doi

  The lack of a better understanding of nuclear effects on the measurement of neutrino properties. The need for more accurate nuclear models in neutrino event generators. The limited ability of current theoretical approaches to reproduce experimental data.

  generalstated research gapevidence 5/5
  Keywords: lack better understanding nuclear effects measurement neutrino properties
• Nucleon decays into three leptons: contact contributions (2026) · Journal of High Energy Physics · doi

  In addition, we present the analysis of an ultraviolet-complete model to demonstrate its connection with our theoretical framework, thereby facilitating further studies of these exotic nucleon decays in upcoming neutrino experiments with large fiducial masses.

  generalabstractevidence 4/5
  Keywords: addition present ultraviolet complete model demonstrate connection theoretical framework thereby facilitating further exotic nucleon decays

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