A Dark Seesaw Solution to Low Energy Anomalies: MiniBooNE, the muon $(g-2)$, and BaBar

Abstract

A recent update from MiniBooNE has strengthened the observed $4.8\sigma$ excess of $e$-like events. Motivated by this and other notable deviations from standard model predictions, such as the muon $(g-2)$, we propose a solution to low energy anomalies through a dark neutrino sector. The model is renormalizable and can also explain light neutrino masses with an anomaly-free and dark $U(1{)}^{\prime }$ gauge symmetry broken at the GeV scale. Large kinetic mixing leads to s-channel production of heavy neutral leptons at $e^{+}{e}^{-}$ colliders, where we point out and explain a $\gtrsim 2\sigma$ excess observed in the BaBar monophoton data. Our model is also compatible with anomalous $e$-like events seen at old accelerator experiments, as well as with an excess of double vertex signatures observed at CCFR.

Comments: v2: Discussion extended, KOTO explanation removed and benchmark points updated. Otherwise, conclusions unchanged. 18 pages, 2 figures, 5 tables. v3: Typos fixed. Accepted for publication in Physics Letters B