Dark sector origin of the KOTO and MiniBooNE anomalies

TL;DR

This paper proposes a dark sector model with a light scalar and sterile neutrino to explain anomalies observed in KOTO, MiniBooNE, and muon magnetic moment measurements, linking these phenomena through new particle interactions.

Contribution

It introduces a novel dark sector framework that unifies explanations for multiple experimental anomalies involving neutrinos and rare meson decays.

Findings

Reproduces KOTO and MiniBooNE anomalies with the dark sector model.

Explains the muon anomalous magnetic moment discrepancy.

Predicts specific decay signatures for future experimental tests.

Abstract

We present a dark sector model that reproduces the KOTO, MiniBooNE and muon anomalous magnetic moment anomalies. The dark sector is comprised of a light scalar singlet $S$ that has a large coupling to a slightly heavier sterile neutrino that mixes with the active neutrinos. The scalar couples to standard model fermions via Yukawa couplings, and to photons via a higher-dimensional coupling. The KOTO signal is a result of the flavor-changing penguin process $K_L \to \pi^0 S$ followed by the decay of $S$ to neutrinos. The sterile neutrino produced in neutrino-nucleus scattering at MiniBooNE decays to an active neutrino and $S$, which decays electromagnetically and creates an event excess at low energies.