Proposal to look for an up/down asymmetry in atmospheric neutrinos beyond Multi-GeV region with existing experimental data

TL;DR

This paper proposes a novel method to analyze high-energy atmospheric neutrinos for up/down asymmetry, aiming to explore neutrino oscillation parameters beyond the Multi-GeV energy range using existing data from underground detectors.

Contribution

It introduces a new approach to test neutrino oscillations at high energies by combining data from multiple detectors, independent of flux and cross-section uncertainties.

Findings

Method is sensitive to oscillation parameters explaining atmospheric neutrino data.

Probes high-energy neutrinos beyond Multi-GeV region.

Limited by statistical strength of KGF observations.

Abstract

We discuss a possible test of neutrino oscillation hypothesis by proposing the combined analysis of high energy atmospheric neutrino induced muon events that have been detected around horizontal direction in the Kolar Gold Field (KGF) underground site and below the horizontal direction by many large detectors such as Super-Kamiokande and MACRO. Up/down asymmetry obtained using contained events recorded by detectors at Kamioka site probes low energy region of atmospheric neutrino whereas, the suggested method probes high energy neutrinos. It mainly depends on the observations and it is free of uncertainties in neutrino flux, interaction cross section etc. In this paper we demonstrate that the method is sensitive to a region of oscillation parameter space that explains all the features of atmospheric neutrino data in the Super-Kamiokande detector; the limiting factor being the statistical strength of the KGF observations. This method provides the only way to study the up/down asymmetry beyond Multi-GeV region which is yet to be measured experimentally.