Addressing the Short-Baseline Neutrino Anomalies with Energy-Dependent Mixing Parameters

TL;DR

This paper proposes that energy-dependent sterile-active neutrino mixing parameters can reconcile short-baseline neutrino anomalies with existing experimental constraints, suggesting a new approach involving sterile neutrino secret interactions.

Contribution

It introduces a novel energy-dependent mixing framework that improves the fit of sterile neutrino models to all neutrino data, including anomalies and disappearance constraints.

Findings

Energy-dependent mixing parameters can reconcile anomalies with constraints.

Secret interactions among sterile neutrinos can produce the observed effects.

The model provides a better fit to experimental data than constant-mixing models.

Abstract

Several neutrino experiments have reported results that are potentially inconsistent with our current understanding of the lepton sector. A candidate solution to these so-called short-baseline anomalies is postulating the existence of new, eV-scale, mostly sterile neutrinos that mix with the active neutrinos. This hypothesis, however, is strongly disfavored once one considers all neutrino data, especially those that constrain the disappearance of muon and electron neutrinos at short-baselines. Here, we show that if the sterile-active mixing parameters depend on the energy-scales that characterize neutrino production and detection, the sterile-neutrino hypothesis may provide a reasonable fit to all neutrino data. The reason for the improved fit is that the stringent disappearance constraints on the different elements of the extended neutrino mixing matrix are associated to production and detection energy scales that are different from those that characterize the anomalous LSND and MiniBooNE appearance data. We show, via a concrete example, that secret interactions among the sterile neutrinos can lead to the results of interest.