Challenge to Anomalous Phenomena in Solar Neutrino

TL;DR

This paper proposes an extended neutrino oscillation model with light sterile neutrinos to explain discrepancies in solar neutrino observations, predicting new mass-squared differences and suggesting future experiments could test this scenario.

Contribution

Introduces a theoretical framework with light sterile neutrinos and composite matter effects to reconcile solar and reactor neutrino data, predicting new oscillation parameters.

Findings

Extended theory with three new mass-squared differences.

Reconciliation of solar and reactor neutrino measurements.

Current data insufficient to confirm the scenario.

Abstract

We suggest a would-be solution to the solar neutrino tension why solar neutrinos appear to mix differently from reactor antineutrinos, in theoretical respect. To do that, based on an extended theory with light sterile neutrinos added we derive a general transition probability of neutrinos born with one flavor tuning into a different flavor. Three new mass-squared differences are augmented in the extended theory: two $\Delta m^2_{\rm ABL}\lesssim{\cal O}(10^{-11})\,{\rm eV}^2$ optimized at astronomical-scale baseline (ABL) oscillation experiments and one $\Delta m^2_{\rm SBL}\sim{\cal O}(1)\,{\rm eV}^2$ optimized at reactor short-baseline (SBL) oscillation experiments. With a so-called composite matter effect that causes a neutrino flavor change via the effects of sinusoidal oscillation including the Mikheyev-Smirnov-Wolfenstein matter effect, we find that the value of $\Delta m^2$ measured from reactor antineutrino experiments can be fitted with that from the $^8$B solar neutrino experiments for roughly $\Delta m^2_1\lesssim10^{-13}\,{\rm eV}^2$ and $\Delta m^2_2\simeq{\cal O}(10^{-11})\,{\rm eV}^2$. Nonetheless, we find that the current data (solar neutrino alone) is not precise enough to test the proposed scenario. Future precise measurements of $^8$B and $pep$ solar neutrinos may confirm and/or improve the value of $\Delta{m}^2_2$.