Neutrino self-interactions in light of DESI and CMB-SPA
Abstract
We present an updated analysis of non-standard neutrino self-interactions, where the interaction is effectively mediated by a heavy particle, using the latest available data from DESI and the CMB. The considered data include combinations of DESI DR1 full-shape galaxy clustering (FS), BAO distance measurements, Lyman-α 1D power spectra (Ly-α), and a combined CMB likelihood (CMB-SPA) using data from Planck, ACT, and SPT. First, we probe two DESI DR1-only datasets, where the effective interaction parameter Geff is multimodal in the profile likelihood, leading us to analyze two different regimes: moderately interacting (MIν) and strongly interacting (SIν) neutrinos. With FS+BAO, the evidence disfavors the SIν mode, a trend that becomes slightly stronger with the inclusion of Ly-α. However, in the latter dataset, the MIν region shows a bimodality in which the intermediate mode is very sharp and peaks around Geff ≃ 10−3 MeV−2; interestingly, this mode is not penalized versus the weaker standard-like mode. Furthermore, we test CMB and DESI joint data and show that the SIν mode is more disfavored by CMB-SPA than by Planck-only data. In particular, the evidence against this mode becomes the strongest thus far (with odds of 5:100000) in the FS+BAO+CMB-SPA combination.
Related
- Consistent treatment of flavour-specific neutrino self-interactions in cosmology
- Latest νs from the Earliest Galaxies: Probing neutrino self-interactions with JWST
- Cosmological preference for a positive neutrino mass at 2.7σ: A joint analysis of DESI DR2, DESY5, and DESY1 data
- Reanalyzing DESI DR1: IV. Percent-level cosmological constraints from combined probes and robust evidence for the normal neutrino mass hierarchy
- Exploring the Limits: Neutrino Mass and Interacting Dark Sector in the DESI Era
BibTeX
@misc{noriega2026neutrino,
title = {{Neutrino self-interactions in light of DESI and CMB-SPA}},
author = {Hernán E. Noriega and Josue De-Santiago and Gabriela Garcia-Arroyo and Ivan Pérez-Castro and Jorge Venzor},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.26654},
eprint = {2610.26654},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.26654},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Neutrino self-interactions in light of DESI and CMB-SPA
AU - Hernán E. Noriega
AU - Josue De-Santiago
AU - Gabriela Garcia-Arroyo
AU - Ivan Pérez-Castro
AU - Jorge Venzor
PY - 2026
DA - 2026/10/19
PB - arXiv
DO - 10.48550/arxiv.2610.26654
UR - https://arxiv.org/abs/2610.26654
AB - We present an updated analysis of non-standard neutrino self-interactions, where the interaction is effectively mediated by a heavy particle, using the latest available data from DESI and the CMB. The considered data include combinations of DESI DR1 full-shape galaxy clustering (FS), BAO distance measurements, Lyman-α 1D power spectra (Ly-α), and a combined CMB likelihood (CMB-SPA) using data from Planck, ACT, and SPT. First, we probe two DESI DR1-only datasets, where the effective interaction parameter G_eff is multimodal in the profile likelihood, leading us to analyze two different regimes: moderately interacting (MI_ν) and strongly interacting (SI_ν) neutrinos. With FS+BAO, the evidence disfavors the SI_ν mode, a trend that becomes slightly stronger with the inclusion of Ly-α. However, in the latter dataset, the MI_ν region shows a bimodality in which the intermediate mode is very sharp and peaks around G_eff ≃ 10^−3 MeV^−2; interestingly, this mode is not penalized versus the weaker standard-like mode. Furthermore, we test CMB and DESI joint data and show that the SI_ν mode is more disfavored by CMB-SPA than by Planck-only data. In particular, the evidence against this mode becomes the strongest thus far (with odds of 5:100000) in the FS+BAO+CMB-SPA combination.
ER -