Peculiar seasonal effects in the neutrino day-night asymmetry

TL;DR

This paper investigates unique seasonal effects in solar neutrino day-night asymmetry, showing that localized contributions can be magnified through weighted observations, potentially revealing hidden neutrino regeneration signatures.

Contribution

It introduces analytical and numerical methods to isolate and magnify localized contributions in the neutrino day-night asymmetry using weighted observation techniques.

Findings

Localized effects can be magnified by weighted observation.

Weighted observation can enhance the amplitude of peculiar contributions.

Feasibility of applying this method in next-generation detectors.

Abstract

We analyze peculiar effects in the day-night asymmetry of solar neutrinos taking place due to their continuous observation during the night and/or the year. Namely, we show that the day-night effect contains both a trivial, cumulative contribution from the whole observation term and a number of localized terms originating from around the midnights (during the nights) and the two solstices (during the year). We estimate the latter contributions using asymptotical methods and discuss the prospects of their isolation, i.e., magnification, by contraction of the neutrino observation term to small neighborhoods of the localization points. In order to complement our asymptotical predictions derived analytically, we also perform a full numerical analysis of a temporally-weighted observation of the day-night effect, including the energy spectrum of the day-night asymmetry and an estimation of the recoil energy distributions for the elastic-scattering detection channel. According to both analytical and numerical results, it turns out that a weighted observation is able to magnify the amplitude of the peculiar contribution to the day-night asymmetry even to as much as several times the cumulative term, and it looks feasible and appealing to perform such a weighting procedure at next-generation detectors to revive otherwise hidden signatures of the neutrino regeneration effect in the Earth.