Diffuse Supernova Neutrinos with Secret Neutrino Interactions
Abstract
The Diffuse Supernova Neutrino Background (DSNB), an isotropic flux arising from the cumulative neutrino emission of all stellar core-collapse events throughout cosmic history, is expected to be detected by next-generation neutrino observatories. As DSNB neutrinos propagate over cosmological distances through the cosmic neutrino background (CνB), they may undergo non-standard neutrino self-interactions (νSI), leaving distinct spectral imprints on the observed flux. In this work, we investigate the impact of scalar (ϕ)-mediated νSI on the DSNB within a full three-flavor framework that retains the complete PMNS structure. We consider four representative flavor-diagonal coupling structures--universal, e-, μ-, and τ-specific. The resonant scattering νiνk→ϕ→νjνl off the lightest, relativistic CνB state produces broad spectral depletion whose pattern depends on the coupling structure and the neutrino mass ordering, generating distinctive signatures across the six flavor fluxes. We compute the resulting event spectra at JUNO, Hyper-Kamiokande with gadolinium loading, and DUNE, and derive projected 3σ sensitivities in the (mϕ, g) parameter plane. We find that these experiments can probe couplings as low as g∼10−8 for mϕ∼100--$300$ eV, surpassing existing bounds by up to a few orders of magnitude in the sub-100 eV mass range. Moreover, unlike the flavor-blind cosmological and supernova bounds, the DSNB sensitivity is flavor-discriminating, offering a unique opportunity to identify the underlying flavor structure of νSI in the event of a detection.
Related
- Probing Scalar-Induced First-Order Phase Transitions with the Diffuse Supernova Neutrino Background
- A Two-Parameter Framework for the Diffuse Supernova Neutrino Background
- Indication of Electron Antineutrinos from the Diffuse Supernova Neutrino Background
- Search for Diffuse Supernova Neutrino Background in the Full KamLAND Dataset with Neural-Network-Based Event Classification
- Search for Diffuse Supernova Neutrino Background in the Full KamLAND Dataset with Neural-network-based Event Classification
BibTeX
@misc{bharadwaj2026diffuse,
title = {{Diffuse Supernova Neutrinos with Secret Neutrino Interactions}},
author = {Praveen Bharadwaj and Utpal Chattopadhyay and Dilip Kumar Ghosh and Arnab Sarker},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.22898},
eprint = {2606.22898},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.22898},
}
RIS
TY - UNPB
TI - Diffuse Supernova Neutrinos with Secret Neutrino Interactions
AU - Praveen Bharadwaj
AU - Utpal Chattopadhyay
AU - Dilip Kumar Ghosh
AU - Arnab Sarker
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2606.22898
UR - https://arxiv.org/abs/2606.22898
AB - The Diffuse Supernova Neutrino Background (DSNB), an isotropic flux arising from the cumulative neutrino emission of all stellar core-collapse events throughout cosmic history, is expected to be detected by next-generation neutrino observatories. As DSNB neutrinos propagate over cosmological distances through the cosmic neutrino background (CνB), they may undergo non-standard neutrino self-interactions (νSI), leaving distinct spectral imprints on the observed flux. In this work, we investigate the impact of scalar (ϕ)-mediated νSI on the DSNB within a full three-flavor framework that retains the complete PMNS structure. We consider four representative flavor-diagonal coupling structures--universal, e-, μ-, and τ-specific. The resonant scattering ν_iν_k→ϕ→ν_jν_l off the lightest, relativistic CνB state produces broad spectral depletion whose pattern depends on the coupling structure and the neutrino mass ordering, generating distinctive signatures across the six flavor fluxes. We compute the resulting event spectra at JUNO, Hyper-Kamiokande with gadolinium loading, and DUNE, and derive projected 3σ sensitivities in the (m_ϕ, g) parameter plane. We find that these experiments can probe couplings as low as g∼10^−8 for m_ϕ∼100--$300$ eV, surpassing existing bounds by up to a few orders of magnitude in the sub-100 eV mass range. Moreover, unlike the flavor-blind cosmological and supernova bounds, the DSNB sensitivity is flavor-discriminating, offering a unique opportunity to identify the underlying flavor structure of νSI in the event of a detection.
ER -