Unifying Solar and Reactor Neutrino Anomalies: Evidence for Sterile Neutrinos as a Dark Matter Candidate

Abstract The long-standing solar neutrino anomaly, characterized by a significant ν e flux deficit relative to the Standard Solar Model (SSM) (Cleveland et al., 1998), and the Reactor An-tineutrino Anomaly (RAA) (Dentler et al., 2018) both strongly suggest the existence of physics beyond the Standard Model. This study presents a unified explanation for these phenomena, focusing on the persistent gallium anomaly (a 10–20% deficit observed at high significance in SAGE, GALLEX/GNO, and BEST (Barinov et al., 2022)) and the RAA (a 6–8% deficit). We propose a 3+1 sterile neutrino model with representative oscillation parameters ∆m 2 41 ≈ 1 eV 2 and sin 2 (2θ 14) ≈ 0.1, derived from global fits (Dasgupta & Kopp, 2021). Using the latest neutrino oscillation parameters from the Particle Data Group (Workman et al., 2022) and Monte Carlo simulations incorporating the Mikheyev-Smirnov-Wolfenstein (MSW) effect, our model consistently describes the data from both solar and reactor experiments. Furthermore, we explore the compelling possibility that a keV-scale sterile neutrino within this framework could serve as a viable warm dark matter candidate (Abazajian, 2017), consistent with current cosmological constraints. We provide predictions for upcoming experiments such as DUNE and PROSPECT, which will decisively test this model.