Preprint proposes DSNB flux distortions as probe of Dirac vs Majorana neutrinos above 10^{-14} μ_B
The preprint demonstrates that DSNB observations could distinguish Dirac from Majorana neutrinos via magnetic-moment-driven chirality flips in magnetorotational supernovae. Detection thresholds are quantified for combined Hyper-Kamiokande and JUNO exposures. Evidence strength is limited by the unknown fraction of such events and reliance on theoretical magnetic-field distributions.
The analysis models neutrino propagation through the intense magnetic fields of a subset of collapsing stars, where magnetic-moment-induced spin-flavor precession converts active neutrinos to sterile states only if neutrinos are Majorana particles. This alters the expected DSNB electron-antineutrino spectrum in a manner independent of mass ordering. The authors calculate that gadolinium-loaded Hyper-Kamiokande combined with JUNO’s inverse-beta-decay statistics would separate the two hypotheses at 99% confidence once the magnetorotational fraction reaches 20%.
The claim rests on a population-synthesis model of core-collapse rates and an assumed magnetic-moment threshold; no new data are presented. Related work on supernova magnetic fields (e.g., 2023 ApJ studies of magnetar progenitors) and DSNB sensitivity projections (Hyper-Kamiokande TDR 2020) supplies the parameter ranges, yet the paper does not propagate uncertainties in the magnetorotational fraction itself.
If confirmed, the result would constitute the first direct cosmological test of neutrino nature outside the lab, bypassing tritium endpoint and neutrinoless-double-beta-decay experiments. It would also tighten bounds on any new physics that couples neutrinos to magnetic fields at the 10^{-14} μ_B scale.
Next steps require improved supernova population statistics from upcoming optical and gravitational-wave surveys to pin down the actual fraction of magnetorotational events before the neutrino detectors accumulate the projected exposure.
Hyper-Kamiokande: First DSNB spectral distortion hint at 2σ within 12 years if magnetorotational fraction exceeds 15%
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2608.14785)
- [2]Supporting Source(https://arxiv.org/abs/2305.00001)