Inference finds consistency between a neutrino flavor evolution model and Earth-based solar neutrino measurements

TL;DR

This paper applies statistical data assimilation to real solar neutrino data to verify the consistency of a neutrino flavor evolution model with Earth-based measurements, confirming the importance of MSW resonance.

Contribution

First use of SDA with real data to validate a neutrino flavor evolution model incorporating MSW resonance effects.

Findings

Model aligns with observed neutrino fluxes when MSW resonance is included.

Demonstrates SDA's effectiveness in analyzing neutrino flavor evolution.

Supports the role of MSW resonance in solar neutrino oscillations.

Abstract

We continue examining statistical data assimilation (SDA), an inference methodology, to infer solutions to neutrino flavor evolution, for the first time using real - rather than simulated - data. The model represents neutrinos streaming from the Sun's center and undergoing a Mikheyev-Smirnov-Wolfenstein (MSW) resonance in flavor space, due to the radially-varying electron number density. The model neutrino energies are chosen to correspond to experimental bins in the Sudbury Neutrino Observatory (SNO) and Borexino experiments, which measure electron-flavor survival probability at Earth. The procedure successfully finds consistency between the observed fluxes and the model, if the MSW resonance - that is, flavor evolution due to solar electrons - is included in the dynamical equations representing the model.