Seasonal Dependence in the Solar Neutrino Flux

TL;DR

This paper investigates the seasonal variation in solar neutrino flux at Super-Kamiokande, highlighting its potential to distinguish between different neutrino oscillation models using recent observational data.

Contribution

It calculates the expected seasonal dependence of neutrino event rates for MSW solutions and compares it with no-oscillation and just-so scenarios based on latest data.

Findings

Seasonal dependence can be significant in large mixing angle MSW solutions.

The seasonal variation correlates with the day-night effect.

Results can help discriminate between MSW and just-so models.

Abstract

MSW solutions of the solar neutrino problem predict a seasonal dependence of the zenith angle distribution of the event rates, due to the non-zero latitude at the Super-Kamiokande site. We calculate this seasonal dependence and compare it with the expectations in the no-oscillation case as well as just-so scenario, in the light of the latest Super-Kamiokande 708-day data. The seasonal dependence can be sizeable in the large mixing angle MSW solution and would be correlated with the day-night effect. This may be used to discriminate between MSW and just-so scenarios and should be taken into account in refined fits of the data.